Since using Google is faster compared to loading the saved Javadoc, I always read the JDK Javadoc online. There was something odd today - the favicon (what's a favicon?) looked a bit off: it's a red square with a white O in the middle.
Heading off to http://java.sun.com/ I see that the header is different. It says "ORACLE: Sun Developer Network (SDN)". So that's where the red favicon comes from !
Well, I guess it will take some getting used to. I don't really know anything about Oracle, but I really liked Sun's logo much more.
Thursday, January 28, 2010
Monday, January 18, 2010
Linux: The last 10% will take another 10 years
Note: The blog post bellow was written on the 6th of December 2007, but I never published it. It seems to still be valid today and given that the laptop I'm talking about went dead and was sent for repairs last week (but most likely they won't be able to fix such an old model), I'm finally publishing it now as a remainder of what that little machine had to endure :-)
Everybody in the Linux world will tell you that Linux has GoodEnoughTM hardware support. Meaning of course that all the good stuff is missing but that your system is fairly functional.
Which is fine ! I mean, as a programmer why would I want to squeeze 100% of my machine ? We can always buy another one which will be even faster but, due to the "LackOfLinuxDriver compensating factor", will fell just like the old machine would have felt with proper drivers.
That is, bad hardware support makes you feel on today's hardware as if you are using a refurbished machine.
Ok, enough ranting. The reason I'm evil in this post is because Linux killed my laptop's battery.
I have an old Dell C840 which had a battery that only lasted about 30 minutes. So I spent about a quarter of the laptop's current value on a new battery (the Dell has two battery bays which is kinda cool).
So now, with the new battery I had about 4 hours off the grid, which was acceptable.
That is, until one night when I just let my laptop with the lid closed but, somehow, it didn't suspend/hibernate as it normally did. Instead it kept on going and going and going upto total and 100% battery drain.
Strangely, the old battery (Li-Ion), after being at 0% and about 16 hours of charge recovered and it's now back to the regular 30 minutes.
But the new battery, after days of charging is dead. Hello LI-Ion deep discharge ! Now, why in the world didn't Linux shutdown my machine when it was clear the power was running out ? Or course, some weird hardware support-related fluke. Do I care ? No: my new battery was killed.
This is sadly a losing position for Linux as they can't write those drivers in some situations (due to so called evil corporations) but it sure makes me mad to use less then what my hardware has to offer...
Another example: Linux (Ubuntu) on a MacBook Pro. It's like the ugly duckling ! The scenario is like this: I use OSX with the nice fonts, Expose, I reboot, I select Linux and then I see the horror. It's as if the machine was reduced to a cheap NoName laptop: the image doesn't "look" good, you see pixelated things, then you see ugly fonts, then you see windows that barely drag/refresh due to lack of a proper driver, then you install the binary-blob-driver from nVidia and notice that the "effects" don't hold a candle to OSX' experience (and some more pixelated stuff).
It's this last 10% threshold that I'm talking about here. Sure, hardware works 90% of the cases, but I sure would like to know I'm using the full power of my machine. Gnome does give you some GUI but I sure would like to see fonts I can stare at for 10 hours a day or some decent effects that aren't there just to show what OpenGL does.
In conclusion: I really like Linux and the reason I bought a Mac was because I needed an "unix" with proper hardware support. Because Linux still doesn't have a place as the main machine.
Linux on a headless server ? Sure ! Linux on my main machine I have to stare at the whole day: not if I have a choice.
Everybody in the Linux world will tell you that Linux has GoodEnoughTM hardware support. Meaning of course that all the good stuff is missing but that your system is fairly functional.
Which is fine ! I mean, as a programmer why would I want to squeeze 100% of my machine ? We can always buy another one which will be even faster but, due to the "LackOfLinuxDriver compensating factor", will fell just like the old machine would have felt with proper drivers.
That is, bad hardware support makes you feel on today's hardware as if you are using a refurbished machine.
Ok, enough ranting. The reason I'm evil in this post is because Linux killed my laptop's battery.
I have an old Dell C840 which had a battery that only lasted about 30 minutes. So I spent about a quarter of the laptop's current value on a new battery (the Dell has two battery bays which is kinda cool).
So now, with the new battery I had about 4 hours off the grid, which was acceptable.
That is, until one night when I just let my laptop with the lid closed but, somehow, it didn't suspend/hibernate as it normally did. Instead it kept on going and going and going upto total and 100% battery drain.
Strangely, the old battery (Li-Ion), after being at 0% and about 16 hours of charge recovered and it's now back to the regular 30 minutes.
But the new battery, after days of charging is dead. Hello LI-Ion deep discharge ! Now, why in the world didn't Linux shutdown my machine when it was clear the power was running out ? Or course, some weird hardware support-related fluke. Do I care ? No: my new battery was killed.
This is sadly a losing position for Linux as they can't write those drivers in some situations (due to so called evil corporations) but it sure makes me mad to use less then what my hardware has to offer...
Another example: Linux (Ubuntu) on a MacBook Pro. It's like the ugly duckling ! The scenario is like this: I use OSX with the nice fonts, Expose, I reboot, I select Linux and then I see the horror. It's as if the machine was reduced to a cheap NoName laptop: the image doesn't "look" good, you see pixelated things, then you see ugly fonts, then you see windows that barely drag/refresh due to lack of a proper driver, then you install the binary-blob-driver from nVidia and notice that the "effects" don't hold a candle to OSX' experience (and some more pixelated stuff).
It's this last 10% threshold that I'm talking about here. Sure, hardware works 90% of the cases, but I sure would like to know I'm using the full power of my machine. Gnome does give you some GUI but I sure would like to see fonts I can stare at for 10 hours a day or some decent effects that aren't there just to show what OpenGL does.
In conclusion: I really like Linux and the reason I bought a Mac was because I needed an "unix" with proper hardware support. Because Linux still doesn't have a place as the main machine.
Linux on a headless server ? Sure ! Linux on my main machine I have to stare at the whole day: not if I have a choice.
Thursday, January 14, 2010
I wonder how much does AllegroGraph cost
Although I'm not a big RDF user, I did notice that some SPARQL queries take some time on my machine so I cannot but ask myself how much faster would it run using AllegroGraph ?
Franz Inc does provide a free edition that's limited on how many triples you may store so at some point it should be easy to run some benchmarks.
But -- how much would the AllegroGraph enterprise license really cost to get rid of the triples limitation ?
Like any company that is (or thinks it is) selling an expensive item, the price is not listed, all you are given is a phone number.
I wonder how many customers are they losing this way because people assume the product is way more expensive then it actually is. Because I won't pay 0.5 million dollars to get the enterprise license. Then again, what do I know, it might be 5 mil plus :-)
Franz Inc does provide a free edition that's limited on how many triples you may store so at some point it should be easy to run some benchmarks.
But -- how much would the AllegroGraph enterprise license really cost to get rid of the triples limitation ?
Like any company that is (or thinks it is) selling an expensive item, the price is not listed, all you are given is a phone number.
I wonder how many customers are they losing this way because people assume the product is way more expensive then it actually is. Because I won't pay 0.5 million dollars to get the enterprise license. Then again, what do I know, it might be 5 mil plus :-)
Monday, January 11, 2010
Personal growth a purpose in itself ?
2 or 3 years ago I used to read some of an internet-famous person's blog posts. They were mostly economical and entrepreneurship related and I liked the way they were written.
Ever since, I stopped reading his blog since his personal growth "road" has taken him into some strange areas I don't really care to follow.
For example, there were some traces of some kind of mysticism, and then he decided he should separate from his wife, then try polyamory and this year he's going into BDSM !
I know the last part since I re-open once in a while his link to see if something interesting might pop-up. Imagine my surprise when I read his latest blog post...
Of course, it could also be some cultural blocks that deny me to see the "value" in what he's is trying to achieve, but I think at some point personal growth might be able to turn malign.
Humans aren't really built for infinite growth given the simple limitation that people die. So, it might be that trying too much to "grow as a person" leads to desensitizing towards normal life. Which means that it's possible to start using more extreme "personal growth" experiences to make up for it.
Ever since, I stopped reading his blog since his personal growth "road" has taken him into some strange areas I don't really care to follow.
For example, there were some traces of some kind of mysticism, and then he decided he should separate from his wife, then try polyamory and this year he's going into BDSM !
I know the last part since I re-open once in a while his link to see if something interesting might pop-up. Imagine my surprise when I read his latest blog post...
Of course, it could also be some cultural blocks that deny me to see the "value" in what he's is trying to achieve, but I think at some point personal growth might be able to turn malign.
Humans aren't really built for infinite growth given the simple limitation that people die. So, it might be that trying too much to "grow as a person" leads to desensitizing towards normal life. Which means that it's possible to start using more extreme "personal growth" experiences to make up for it.
Go see Avatar
Yesterday I watched Avatar in a proper cinema with 3D glasses. The experience was almost surreal and while I had already read the book long ago, the adaptation was decent.
But really -- the 3D part of the movie is where all the magic is. Well worth the ticket price !
But really -- the 3D part of the movie is where all the magic is. Well worth the ticket price !
Monday, January 04, 2010
No such thing as a bad technology
The human race will adapt to the tools and technologies it has developed. That's why the cell phone companies for example just have to play a long term game and wait: in time fewer people will be sensitive to their cell phone radiation.
It's just another level in the "adapting to the environment" game. Even if this time the environment is man-made.
It's just another level in the "adapting to the environment" game. Even if this time the environment is man-made.
Wednesday, December 09, 2009
Logging needs some lazy evaluation
If it's one situation where lazy evaluation is needed in Java, it's logging. Until something better comes up and we'll have logging injected via AOP or something similar, a log message will be just the result of an extra line in our Java files, and this is a problem.
A normal log message is something like this:
log.fine("Some parameter is:" + someVariable);
This looks quite harmless especially since we know that depending on the log level, our message might be saved or not.
But say we have an expensive function:
log.fine("The extra informations starts at" + reallyLongLastingFunction());
The problem above is obvious: the log string will be built no matter what and our reallyLongLastingFunction() will be called each time, including when the log won't actually be saved.
The solution to this is to pollute your code with something like:
if(log.isLoggable(Level.FINE)){
log.fine("The extra informations starts at" + reallyLongLastingFunction());
}
This way our string creation and expensive function call is done only if the log really is needed. But this adds extra boilerplate in the code as well as makes you maintain the log level (for example what if I change the line to log.finer -- I have to update the if).
If all the log methods would have lazy evaluation this problem would go away -- the code won't be executed until actually needed and there will be only one line in the code.
The AOP style is to inject the logging using bytecode engineering. Perhaps it would be nice to do a post-processing of the resulted JAR artifacts and replace all log calls with something that injects that if check, etc.
And speaking of memory and CPU wasted on logging, there's nothing like seeing that your biggest CPU user is caused by the increased log level while debugging. Debuggers should know how to filter log calls, including time spent in the string building itself otherwise they don't really help.
Friday, October 23, 2009
Official NetBeans build with Romanian localization
Head over to the NetBeans download website and notice the language popup also has Romanian now.
More info about the localization on the Joseki Bold dedicated page.
More info about the localization on the Joseki Bold dedicated page.
Sunday, October 11, 2009
Aversion towards localization a sign of technological barbarism
English is obviously the lingua-franca of everything computer and computer-science related. Having a single language does help everybody since it easily allows people to communicate and exchange ideas.
The side-effect of using English for everything computer related is that it decreases the focus on using the local language for computer-related discussions. Or, if the local language is used, it is filled with English words ! The more complex the discussion becomes, the more English is used until it becomes almost easier to use English full-time and just revert to the local language when some explaining is required using examples. I think this is the reason some multinationals revert to English as the official language -- for computer related workers, it doesn't affect the productivity, especially since people of different nationalities might end up working together.
Well, this means that while English has evolved to be a technology-centric language, most of the other languages either try to play catch-up or, most likely, don't run into the race at all and just import all the English words.
In my country developers, for example, dislike applications localized into the native language. The more technical the application is (like a developer tool), the more foreign it seems to them to see the text in the local language instead of English. Native words disturb them and metaphors seem weird when they make the cognitive connection: a mouse is actually a rodent ! I'm pretty sure English people also thought of rodents the first time they heard "mouse" in a phrase -- but this has been changed nowadays. Computers have become so ubiquitous that "mouse" usually means that computer peripheral. "Firewall" is not some fireman expression or a burning wall, but something computer related, etc.
By focusing so much on the English language and not allowing themselves to jump-start the native language metaphors related to computer science, developers are the main culprit of keeping the native language into a phase of technological barbarism.
An then, they act surprised when the local market almost doesn't exist and their parents can't understand a thing from computers and need help with the simplest things (usually they can't understand the language on screen, which is English).
The side-effect of using English for everything computer related is that it decreases the focus on using the local language for computer-related discussions. Or, if the local language is used, it is filled with English words ! The more complex the discussion becomes, the more English is used until it becomes almost easier to use English full-time and just revert to the local language when some explaining is required using examples. I think this is the reason some multinationals revert to English as the official language -- for computer related workers, it doesn't affect the productivity, especially since people of different nationalities might end up working together.
Well, this means that while English has evolved to be a technology-centric language, most of the other languages either try to play catch-up or, most likely, don't run into the race at all and just import all the English words.
In my country developers, for example, dislike applications localized into the native language. The more technical the application is (like a developer tool), the more foreign it seems to them to see the text in the local language instead of English. Native words disturb them and metaphors seem weird when they make the cognitive connection: a mouse is actually a rodent ! I'm pretty sure English people also thought of rodents the first time they heard "mouse" in a phrase -- but this has been changed nowadays. Computers have become so ubiquitous that "mouse" usually means that computer peripheral. "Firewall" is not some fireman expression or a burning wall, but something computer related, etc.
By focusing so much on the English language and not allowing themselves to jump-start the native language metaphors related to computer science, developers are the main culprit of keeping the native language into a phase of technological barbarism.
An then, they act surprised when the local market almost doesn't exist and their parents can't understand a thing from computers and need help with the simplest things (usually they can't understand the language on screen, which is English).
Thursday, September 24, 2009
Green software
Long ago I wrote a blogpost where I was mentioning that for an always-on (wall-plugged) workstation, the latest (then) fad of lowering power consumption is not that essential since, as a developer, all you care about is overall machine speed to get the job done and the cost of power is negligible compared to the cost of on developer hour (and then rent, administrative overhead, etc.)
Well, that is one aspect. The other aspect is when power consumption is important. This is clearly a major factor for large datacenters where a big chunk of their cost is power (for the machines and cooling) so they keep a keen eye on performance per watt. The specifics of the business are different there: you don't have developers on top of each machine, but you have hundreds / thousands of machines providing some service to remote users. The cost of maintaining that datacenter determines the cost you sell your services to users and your overall competitiveness.
Another scenario I've personally noticed as of late (see my other article somehow related to this) is the importance of performance per watt when working on your laptop's battery !
Now, the overall system performance per watt is a given of the machine you happen to own. You can't actually tweak that very much, except some hardware upgrade here and there and operating system optimization.
So what you are left is the actual software you use everyday and its performance per watt. Let's call that productivity per watt. Lower performing sofware might exhibit different issues:
These are all optimization issues but the main culprit is not scaling down when on battery: this includes being smart about redundant tasks like re-indexing the Maven repository or checking of non-essential upgrades that could be deferred to a time when you're not on laptop battery .
What we seem to be missing is a new metric to evaluate applications: productivity per watt and teaching users to pick applications the same way they pick an A+ energy rating fridge.
Looking forward to see which IDE uses less power to refactor a class or just to stay idle.
Well, that is one aspect. The other aspect is when power consumption is important. This is clearly a major factor for large datacenters where a big chunk of their cost is power (for the machines and cooling) so they keep a keen eye on performance per watt. The specifics of the business are different there: you don't have developers on top of each machine, but you have hundreds / thousands of machines providing some service to remote users. The cost of maintaining that datacenter determines the cost you sell your services to users and your overall competitiveness.
Another scenario I've personally noticed as of late (see my other article somehow related to this) is the importance of performance per watt when working on your laptop's battery !
Now, the overall system performance per watt is a given of the machine you happen to own. You can't actually tweak that very much, except some hardware upgrade here and there and operating system optimization.
So what you are left is the actual software you use everyday and its performance per watt. Let's call that productivity per watt. Lower performing sofware might exhibit different issues:
- Consuming too much CPU
- Hitting the disk too often. IDEs are notoriously culprits here when a normal clean build deletes and recreates hundreds of files on disk. Even some feature like compile on save doesn't save much since developers save often and all this disk writing might actually stop the disk from going to sleep (and thus consume less power).
- Hitting the network too often or too much. No point in checking for software updates when the user is on battery. No point downloading that 200MB "update" file -- updates should consist of binary diffs and be as small as possible (Google is looking into this as it becomes very important the more users you have). Also, laptops generally use WiFi is they are not plugged in and (I think) that consumes even more power than ethernet.
These are all optimization issues but the main culprit is not scaling down when on battery: this includes being smart about redundant tasks like re-indexing the Maven repository or checking of non-essential upgrades that could be deferred to a time when you're not on laptop battery .
What we seem to be missing is a new metric to evaluate applications: productivity per watt and teaching users to pick applications the same way they pick an A+ energy rating fridge.
Looking forward to see which IDE uses less power to refactor a class or just to stay idle.
Tuesday, September 22, 2009
Just released Romanian translation of the NetBeans Platform
Just released Romanian translation of the NetBeans Platform. See more on my company's website.
Thursday, August 20, 2009
Monday, August 17, 2009
Wednesday, July 15, 2009
The most complex simple GUI: VirtualBox snapshot handling
It's amazing how the guys doing Virtual Box (purchased by Sun and now by Oracle) have managed to screw up so badly their snapshot mechanism and specifically their GUI allowing the user to handle it:
Also, not only did they pick such a wrong wording and show such lack in clearly explaining what their application is supposed to do, but they don't even seem to find this important. A bug report on their website complaining about this very thing is marked as minor !
I guess this is a sign of some geek mentality. They assume that people must train using the uber-software and actually read and memorize the 250 page PDF (probably at some point it all makes sense). The sad thing is that the GUI is really simple and this minimalism should allow them to focus on the details, but a third of it is broken.
Obviously I'm not talking about their "Settings" GUI where you configure the machine, that's very complex.
I'm talking about the normal GUI the users gets to see every other time after the creation of the virtual machine which has 3 tabs: "Details", "Snapshots" and "Description". The only one the user will interact for the rest of the virtual machine's lifetime is "Snapshots" and this is the one they thought it's minor. Go figure.
1. Let's start with the easy pickings: they support linear snapshots only. What did they select to display this? Obviously not a list, but a tree !
2. Their snapshot documentation is less than 1 page in the PDF help file. Out of this, half is spent explaining how to "take" a snapshot which is probably the easiest thing they support. A quarter of the page includes a scary note about possible data loss which references some VBoxManage interface which is some script that has nothing to do with the GUI.
Also, their documentation doesn't have a single screenshot or at least pictures of the buttons users are supposed to press.
In the remaining quarter of the documentation they briefly mention revert and discard snapshot.
At no point do they bother explaining how their mechanism works, you kinda have to read between the lines what the philosophy is.
3. When you press "Discard snapshot" it actually merges changes. So you're not losing data actually, you're just losing the little timestamp that the snapshot gave you. They couldn't have picked a more confusing wording and it's not what you would expect.
4. Next to the notion of "snapshot" they have a separate notion of "current state" or "state" which is somehow related but kinda different. I'm not entirely certain if "state" is something like a placeholder that I can fill with different snapshots or just the tip of the snapshots list. Their wording makes it sound one or the other.
Also, not only did they pick such a wrong wording and show such lack in clearly explaining what their application is supposed to do, but they don't even seem to find this important. A bug report on their website complaining about this very thing is marked as minor !
I guess this is a sign of some geek mentality. They assume that people must train using the uber-software and actually read and memorize the 250 page PDF (probably at some point it all makes sense). The sad thing is that the GUI is really simple and this minimalism should allow them to focus on the details, but a third of it is broken.
Obviously I'm not talking about their "Settings" GUI where you configure the machine, that's very complex.
I'm talking about the normal GUI the users gets to see every other time after the creation of the virtual machine which has 3 tabs: "Details", "Snapshots" and "Description". The only one the user will interact for the rest of the virtual machine's lifetime is "Snapshots" and this is the one they thought it's minor. Go figure.
Tuesday, March 03, 2009
Matrix thoughts
AI lemma (anti-Matrix):
A corollary would be:
We do not live in a simulation of a similar universe as a simulation will consume more energy than a real existence.
A corollary would be:
The universe simulating our existence might be so different that the above lemma doesn't apply.
Monday, February 02, 2009
iPhone Location Manager taking forever
On the iPhone, the Location manager that provides the GPS location is a nice API to use.
It does have some issues though: CLLocationManger doesn't work if it's called from another thread !
I first noticed something was really funny when my delegate wasn't being called at all.
Neither – locationManager:didUpdateToLocation:fromLocation: nor – locationManager:didFailWithError: was called and my application was just waiting there forever for some GPS information.
My first thought was that it was some issue with my memory management as I wasn't holding a reference to the location manager in any class, just in the method where it was created. But still, it didn't work.
Then, I though it was a problem about the threading model being used (I waited for the GPS location in another thread in order not to block the GUI). Sure enough, that seemed to be the problem, and at least another person complained about it. Not sure it is a matter of threading or a matter of memory pool being used.
But more to the point, always create your CLLocationManager instance in the main thread, and not in another thread. Having a singleton method there which is called from the main thread somewhere assures you that the location manager is created in the proper thread/pool.
It does have some issues though: CLLocationManger doesn't work if it's called from another thread !
I first noticed something was really funny when my delegate wasn't being called at all.
Neither – locationManager:didUpdateToLocation:fromLocation: nor – locationManager:didFailWithError: was called and my application was just waiting there forever for some GPS information.
My first thought was that it was some issue with my memory management as I wasn't holding a reference to the location manager in any class, just in the method where it was created. But still, it didn't work.
Then, I though it was a problem about the threading model being used (I waited for the GPS location in another thread in order not to block the GUI). Sure enough, that seemed to be the problem, and at least another person complained about it. Not sure it is a matter of threading or a matter of memory pool being used.
But more to the point, always create your CLLocationManager instance in the main thread, and not in another thread. Having a singleton method there which is called from the main thread somewhere assures you that the location manager is created in the proper thread/pool.
Friday, January 30, 2009
Developer surprise on OSX
I had a strange bug in the OSX Address Book application: I had a rule that included all the address cards not present in any other rule.
This worked initially, but after an update, Address Book got confused and entered into an infinite cycle (it was probably trying to ignore the cards in the rule itself and then went on to resolve that recursively).
Anyhow, the good thing was the application crashed only if I scrolled on top of that particular rule. And since I had quite a lot, I was safe to open the application at least.
But, still, having a semi-buggy application isn't fun to use. So I went and looked at the Address Book file format which seemed to be some sqlite3 database, but I couldn't fix the problem from there.
To my surprise Apple has a public API for the Address Book !
So I wrote these short lines of code:
This worked initially, but after an update, Address Book got confused and entered into an infinite cycle (it was probably trying to ignore the cards in the rule itself and then went on to resolve that recursively).
Anyhow, the good thing was the application crashed only if I scrolled on top of that particular rule. And since I had quite a lot, I was safe to open the application at least.
But, still, having a semi-buggy application isn't fun to use. So I went and looked at the Address Book file format which seemed to be some sqlite3 database, but I couldn't fix the problem from there.
To my surprise Apple has a public API for the Address Book !
So I wrote these short lines of code:
ABAddressBook *AB = [ABAddressBook sharedAddressBook];and that was it ! No more Address Book crashes ! Turns out OSX is really nice to tweak if you are willing to code a bit.
NSArray * groups = [AB groups];
for(int i=0;i<[groups count];i++){
ABGroup * group = [groups objectAtIndex:i];
NSString * name = [group valueForProperty: kABGroupNameProperty];
if([@"BadBadRule" compare:name]==NSOrderedSame){
[AB removeRecord:group];
[AB save];
}
}
Wednesday, January 14, 2009
My Slicehost / VPS analysis
Fist time VPS user
Starting a few months back, I have a VPS from Slicehost. It's the cheapes one they've got, with only 256MB RAM.
I never worked on a VPS, I only had either dedicated physical servers in the company datacenter (at the previous job) or CPanel-based hosted accounts (for some other clients).
All in all, a VPS is just as one might expect: almost like a normal server only slower.
And the slowness is starting to bug me a bit, specifically the problem that I don't know how slow is it supposed to be.
The fixed technical details from Slicehost is that you'll have 256MB RAM, 10GB or disk storage and 100GB bandwidth.
Now there are 2 issues here. One which seems quite obvious and another one I'll introduce later.
CPU
OK, the 1st problem is that you don't know how much CPU cycles you are going to get. Being a VPS means it runs on some beefy server (Slicehost says it's a Quad core server with 16GB of RAM).
According to Slicehost's FAQ:
This basically means that under load, each slices gets CPU cycles depending on the RAM it has (ie. price you pay). A 256MB slice gets 1 cycle, the 512MB slice gets 2 cycles, 1GB slice gets 4 cycles and so on.
The problem here is of course, that one is not certain that they only have on the server a maximum amount of slices, but Slicehost is clearly overselling as top usually displays a "Steal time" of around 20%.
So, assuming a machine is filled 100% with slices and there is no multiplexing, it means that a 256MB slice gets 6.25% of a single CPU under load.
6.25 isn't much at all, but considering that the machine isn't always under load, the slice seems to get a decent amount of CPU nonetheless.
If we consider the overselling issue and that 20% is stolen by Xen to give to other VPS, we get to an even 5 %.
Now, this might not be as bad as it sounds CPU-wise as I've noticed Xen stealing time when my CPU-share is basically idle anyhow so maybe it doesn't affect my overall performance.
For example: ./pi_css5 1048576 takes about 10 seconds which is more than decent.
IO
The bigger problem with VPS seems the be the fact that hard drives aren't nearly as fast as RAM. And when you have a lot of processes competing for the same disk, it's bound to be slow.
What Slicehost doesn't mention is if the "fixed weight" sharing rule they use for CPU cycles applies to disk access too. My impression is that it is.
After trying to use my VPS as a build server I've noticed it grind to a halt.
top shows something like this:
but the load average for a small build is something like
So, looking at the information above, we can note that 62.2%, the CPU is just idle, while the actualy "working" tasks, ie. 20.9% are waiting for IO. The rest of 16.9% CPU time is stolen by Xen and given to other virtual machines, and I don't think it really matters given that the load is clearly IO-bound.
And here lies the problem: just how fast might Slicehosts' hard drives be ? And how many per slice ? Actually more like: how many slices per drive ?
From a simple test I made, a simple build that takes 30 seconds on my MacBook Pro (2.4Ghz/2GB ram/laptop hard drive-5400rpm) takes about 20 minutes on the slice. This means the VPS is 40 times slower when doing IO-bound tasks.
Another large build that takes around 40 minutes on my laptop took 28 hours on the server. Which respects the about 40 times slower rule.
Now considering the above number and a 20% steal time, I'd expect to have a 20% overselling of slices on a physical machine. Meaning, at 16GB per machine, roughly 76 slices of 256MB on one machines. Taking into account the 1:40 rule above for IO speed, this means that they have about 2 hard drives in a server.
Conclusions
It's certainly liberating to have complete control over a server. CPanel solution just don't cut it when you need to run various applications on strange ports. Of course, the downsize is that you also have to do all the administration tasks, secure it, etc.
The Slice host services are very decent price-wise, the "administrator" panel they have provides you with everything you need, even a virtual terminal that goes to tty1 of the machine (very handy if for some reason SSH doesn't work for example).
Even the smallest slice I'm using right now has enough space, RAM and bandwidth for small tasks. If you just use it sparingly during business hours, the "fixed weight" sharing rule gives you enough CPU / IO for most tasks.
But for heavy usage, I think the solution is either to get a more expensive slice or start building your own machine.
IO-bound tasks are almost impossible to run due to the 1:40 slowness noticed. This means that you need to get at least the 4GB slice to have it run decently. Of course, that's $250 compared to the $20 slice I have right now.
CPU doesn't seem to be a problem, at least for my kind of usage. It seems responsive enough during normal load and mostly idle under heavy load (so idle that Xen gives my CPU cycles to other virtual machines). Initially I was expecting this to be a major problem while moving my build server there, but boy, was I wrong. IO-limitations don't even compare with the CPU limitations.
Getting 5% or more of a fast CPU doesn't even compare to getting 2.5% of an even slower resource like that hard drive if you are compiling.
Further experiments
During the time I was considering the CPU to be my future bottleneck, I was thinking which option would be better: 2 x 256MB slices or a bigger 512MB slice.
According to their rules and offering, the two configurations are totally comparable. Even more, using their sharing rule, 2 x 256MB slices should get at least the same CPU cycles under load as the 512MB one. (Further emails from Slicehost's support led me to believe the rule might be oversimplified, but they didn't tell me in what way -- I think the weight of the smallest slices might be even smaller with the bigger slices getting even more of their share).
So, if under load they get the same CPU cycles, it means that when the machine has CPU cycles to spare, I have 2 candidate slices to get those spares.
So the question was: for a 5% price increase I would pay for 2 x 256 slices compared to 1 x 512 slice, will I get at least 5% more CPU cycles ?
I'm still not certain with the data I've computed that it might happen. Also, the new question now would be: will I get at least 5% more IO operations ?
Non-agression
The above post isn't a rant against Slicehost. I think they are providing a decent service for their price. It is interesting though to see which kind of usage can one put on a VPS and which are better to be run on the server in the basement.
512MB update
Well, isn't this interesting. A vertical upgrade to 512MB of RAM is another world entirely. Maybe the new VPS is on a less-loaded machine, but at first sight, it's looking way better: the previous 28 hours build (fresh) takes now only 40 minutes for a small update. I'll try a clean build later this week and see how fast it is.
So it seems it wasn't only a problem of slow IO, it was also a big problem of not enough RAM leading to swap file trashing.
Starting a few months back, I have a VPS from Slicehost. It's the cheapes one they've got, with only 256MB RAM.
I never worked on a VPS, I only had either dedicated physical servers in the company datacenter (at the previous job) or CPanel-based hosted accounts (for some other clients).
All in all, a VPS is just as one might expect: almost like a normal server only slower.
And the slowness is starting to bug me a bit, specifically the problem that I don't know how slow is it supposed to be.
The fixed technical details from Slicehost is that you'll have 256MB RAM, 10GB or disk storage and 100GB bandwidth.
Now there are 2 issues here. One which seems quite obvious and another one I'll introduce later.
CPU
OK, the 1st problem is that you don't know how much CPU cycles you are going to get. Being a VPS means it runs on some beefy server (Slicehost says it's a Quad core server with 16GB of RAM).
According to Slicehost's FAQ:
Each Slice is assigned a fixed weight based on the memory size (256, 512 and 1024 megabytes). So a 1024 has 4x the cycles as a 256 under load. However, if there are free cycles on a machine, all Slices can consume CPU time.
This basically means that under load, each slices gets CPU cycles depending on the RAM it has (ie. price you pay). A 256MB slice gets 1 cycle, the 512MB slice gets 2 cycles, 1GB slice gets 4 cycles and so on.
The problem here is of course, that one is not certain that they only have on the server a maximum amount of slices, but Slicehost is clearly overselling as top usually displays a "Steal time" of around 20%.
So, assuming a machine is filled 100% with slices and there is no multiplexing, it means that a 256MB slice gets 6.25% of a single CPU under load.
6.25 isn't much at all, but considering that the machine isn't always under load, the slice seems to get a decent amount of CPU nonetheless.
If we consider the overselling issue and that 20% is stolen by Xen to give to other VPS, we get to an even 5 %.
Now, this might not be as bad as it sounds CPU-wise as I've noticed Xen stealing time when my CPU-share is basically idle anyhow so maybe it doesn't affect my overall performance.
For example: ./pi_css5 1048576 takes about 10 seconds which is more than decent.
The bigger problem with VPS seems the be the fact that hard drives aren't nearly as fast as RAM. And when you have a lot of processes competing for the same disk, it's bound to be slow.
What Slicehost doesn't mention is if the "fixed weight" sharing rule they use for CPU cycles applies to disk access too. My impression is that it is.
After trying to use my VPS as a build server I've noticed it grind to a halt.
top shows something like this:
Cpu(s): 0.0%us, 0.0%sy, 0.0%ni, 62.2%id, 20.9%wa, 0.0%hi, 0.0%si, 16.9%st
but the load average for a small build is something like
and it easily goes to 3, 4 and even 9! when I also try to do something else there.
load average: 1.73, 2.06, 1.93
So, looking at the information above, we can note that 62.2%, the CPU is just idle, while the actualy "working" tasks, ie. 20.9% are waiting for IO. The rest of 16.9% CPU time is stolen by Xen and given to other virtual machines, and I don't think it really matters given that the load is clearly IO-bound.
And here lies the problem: just how fast might Slicehosts' hard drives be ? And how many per slice ? Actually more like: how many slices per drive ?
From a simple test I made, a simple build that takes 30 seconds on my MacBook Pro (2.4Ghz/2GB ram/laptop hard drive-5400rpm) takes about 20 minutes on the slice. This means the VPS is 40 times slower when doing IO-bound tasks.
Another large build that takes around 40 minutes on my laptop took 28 hours on the server. Which respects the about 40 times slower rule.
Now considering the above number and a 20% steal time, I'd expect to have a 20% overselling of slices on a physical machine. Meaning, at 16GB per machine, roughly 76 slices of 256MB on one machines. Taking into account the 1:40 rule above for IO speed, this means that they have about 2 hard drives in a server.
Conclusions
It's certainly liberating to have complete control over a server. CPanel solution just don't cut it when you need to run various applications on strange ports. Of course, the downsize is that you also have to do all the administration tasks, secure it, etc.
The Slice host services are very decent price-wise, the "administrator" panel they have provides you with everything you need, even a virtual terminal that goes to tty1 of the machine (very handy if for some reason SSH doesn't work for example).
Even the smallest slice I'm using right now has enough space, RAM and bandwidth for small tasks. If you just use it sparingly during business hours, the "fixed weight" sharing rule gives you enough CPU / IO for most tasks.
But for heavy usage, I think the solution is either to get a more expensive slice or start building your own machine.
IO-bound tasks are almost impossible to run due to the 1:40 slowness noticed. This means that you need to get at least the 4GB slice to have it run decently. Of course, that's $250 compared to the $20 slice I have right now.
CPU doesn't seem to be a problem, at least for my kind of usage. It seems responsive enough during normal load and mostly idle under heavy load (so idle that Xen gives my CPU cycles to other virtual machines). Initially I was expecting this to be a major problem while moving my build server there, but boy, was I wrong. IO-limitations don't even compare with the CPU limitations.
Getting 5% or more of a fast CPU doesn't even compare to getting 2.5% of an even slower resource like that hard drive if you are compiling.
Further experiments
During the time I was considering the CPU to be my future bottleneck, I was thinking which option would be better: 2 x 256MB slices or a bigger 512MB slice.
According to their rules and offering, the two configurations are totally comparable. Even more, using their sharing rule, 2 x 256MB slices should get at least the same CPU cycles under load as the 512MB one. (Further emails from Slicehost's support led me to believe the rule might be oversimplified, but they didn't tell me in what way -- I think the weight of the smallest slices might be even smaller with the bigger slices getting even more of their share).
So, if under load they get the same CPU cycles, it means that when the machine has CPU cycles to spare, I have 2 candidate slices to get those spares.
So the question was: for a 5% price increase I would pay for 2 x 256 slices compared to 1 x 512 slice, will I get at least 5% more CPU cycles ?
I'm still not certain with the data I've computed that it might happen. Also, the new question now would be: will I get at least 5% more IO operations ?
Non-agression
The above post isn't a rant against Slicehost. I think they are providing a decent service for their price. It is interesting though to see which kind of usage can one put on a VPS and which are better to be run on the server in the basement.
512MB update
Well, isn't this interesting. A vertical upgrade to 512MB of RAM is another world entirely. Maybe the new VPS is on a less-loaded machine, but at first sight, it's looking way better: the previous 28 hours build (fresh) takes now only 40 minutes for a small update. I'll try a clean build later this week and see how fast it is.
So it seems it wasn't only a problem of slow IO, it was also a big problem of not enough RAM leading to swap file trashing.
Friday, November 07, 2008
I guess it has begun: the environment is at fault for everything
I'm always amazed at the amount of bullshit people are able to come up with, especially when explaining some corporate move.
Take for example my main bank BRD - Groupe Société Générale. Yes, it's the same Groupe Société Générale which showed at the end of 2007 a € 4.9 billion fraud. But it's OK since the Romanian branch is really profitable for them due to limited consumer education here and powerless consumer protection institutions.
I just noticed a new message from them on the Internet Banking site: due to increased environmental awareness from the Bank, they are encouraging people to get alternative bank account statements via online banking or by post. Otherwise you are entitled to one printed account statement per month from their offices.
The reason is, of course, to save the trees by printing less. Of course they are willing to print tons of the stuff if you are willing to pay -- which will go directly into their profit but that's another problem, no ?
Also add here that they also increased the tax for having an account by 20% for individuals and 50% for companies. That probably also had some environmental reasoning that's escaping me.
Anyhow, I'm looking forward to more price increases and consumer ripoffs that's going to be done in the name of the trees.
Too bad us people can't buy our own carbon credit so that companies won't be able to offset that extra cost in the name of the environment on us. But you know what ? I'm pretty sure some one will introduce carbon credit for the masses. After all, why not ? It's a nice way to bring some more money to the state budget.
And only then that old saying will come true: they'll tax you for the air you breath !
Well, technically for the air you exhale but we're close enough.
Take for example my main bank BRD - Groupe Société Générale. Yes, it's the same Groupe Société Générale which showed at the end of 2007 a € 4.9 billion fraud. But it's OK since the Romanian branch is really profitable for them due to limited consumer education here and powerless consumer protection institutions.
I just noticed a new message from them on the Internet Banking site: due to increased environmental awareness from the Bank, they are encouraging people to get alternative bank account statements via online banking or by post. Otherwise you are entitled to one printed account statement per month from their offices.
The reason is, of course, to save the trees by printing less. Of course they are willing to print tons of the stuff if you are willing to pay -- which will go directly into their profit but that's another problem, no ?
Also add here that they also increased the tax for having an account by 20% for individuals and 50% for companies. That probably also had some environmental reasoning that's escaping me.
Anyhow, I'm looking forward to more price increases and consumer ripoffs that's going to be done in the name of the trees.
Too bad us people can't buy our own carbon credit so that companies won't be able to offset that extra cost in the name of the environment on us. But you know what ? I'm pretty sure some one will introduce carbon credit for the masses. After all, why not ? It's a nice way to bring some more money to the state budget.
And only then that old saying will come true: they'll tax you for the air you breath !
Well, technically for the air you exhale but we're close enough.
Thursday, August 07, 2008
No new mail! Want to read updates from your favorite sites?
For a while now I've started using GMail's "Archive" button aggressively on my inbox. The end result has been that from thousands of emails, I now have 0 (zero) ! Everything is archived.
When I get a new email, it sits in the Inbox until it is resolved (ie. I reply or read it). Then it's instantly archived. Out of sight, out of mind.
I've found that this technique greatly reduces the information overload coming from emails. With a full inbox that was also showing snippets of the message (ie. small previews), every time I looked at my inbox I had some information to process. Like: oh, look, that one is starred, I wonder when they'll reply or hm, it's been quite some time since I've got an email from X as the name is on the bottom on the inbox, etc. etc.
Basically a full inbox sends you some information even when no unread emails exist. It's also quite a bad way to "search" for email. I used to manually look for some subject and/or sender in order to hit reply. Now I just use GMail's search.
I remember about some TED video where the host said something like our brain likes new information, we have an addiction for new stuff. Which is exactly what email feeds. It feeds our addiction for new things, even by just having a full list of previously received emails. I also assume that's why sites like Slashdot, Digg and Reddit are quite popular: they feed us new, easy to process, information. Imagine brain junk-food if you will or the Internet-equivalent of too much TV will rot your brain.
Related to this need to always get new stuff, I find it interesting the way Google handles this. When your inbox is empty, you get this message: No new mail! Want to read updates from your favorite sites? Try Google Reader (with a link to google reader).
So what Google is doing here is proving us what we have become used to. Not enough interruptions, not enough new stuff from email? Why gee, why don't you try this other source of new things: Google Reader. Come on, get a quick fix !
When I get a new email, it sits in the Inbox until it is resolved (ie. I reply or read it). Then it's instantly archived. Out of sight, out of mind.
I've found that this technique greatly reduces the information overload coming from emails. With a full inbox that was also showing snippets of the message (ie. small previews), every time I looked at my inbox I had some information to process. Like: oh, look, that one is starred, I wonder when they'll reply or hm, it's been quite some time since I've got an email from X as the name is on the bottom on the inbox, etc. etc.
Basically a full inbox sends you some information even when no unread emails exist. It's also quite a bad way to "search" for email. I used to manually look for some subject and/or sender in order to hit reply. Now I just use GMail's search.
I remember about some TED video where the host said something like our brain likes new information, we have an addiction for new stuff. Which is exactly what email feeds. It feeds our addiction for new things, even by just having a full list of previously received emails. I also assume that's why sites like Slashdot, Digg and Reddit are quite popular: they feed us new, easy to process, information. Imagine brain junk-food if you will or the Internet-equivalent of too much TV will rot your brain.
Related to this need to always get new stuff, I find it interesting the way Google handles this. When your inbox is empty, you get this message: No new mail! Want to read updates from your favorite sites? Try Google Reader (with a link to google reader).
So what Google is doing here is proving us what we have become used to. Not enough interruptions, not enough new stuff from email? Why gee, why don't you try this other source of new things: Google Reader. Come on, get a quick fix !
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