Linux 2.6.20-rc6 Kernel Performance 226
Michael writes "The Linux 2.6.20 kernel will feature KVM support, Playstation 3 support, and a variety of other improvements. With the Linux 2.6.20-rc6 kernel out the door, Phoronix has written a performance comparison of the Linux 2.6.20-rc6 kernel against the 2.6.19 and 2.6.19.2 kernels in a variety of benchmarks."
PS-3 (Score:2, Insightful)
Why is playstation support being included in the kernel? Is that really necessary?
Furthermore, the article didn't exactly make it clear what the support is. Can anyone clarify?
Re:PS-3 (Score:5, Insightful)
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Re:PS-3 (Score:5, Informative)
Re:PS-3 (Score:5, Insightful)
Yeah, don't forget why most folks start tinkering with Linux in the first place.
- We love to tinker
- We want closer access to the hardware
- Somebody told us we can't, so that just makes us want to all the more
All three apply to the PS3, as far as I'm concerned!Re: (Score:2)
Re:PS-3 (Score:4, Insightful)
The only current restriction is there isn't accelerated OpenGL from the RSX. You can write an OpenGL ES implementation for Cell and get pretty good performance. I ran OpenGL on top of just the VUs on PS2 RTE and got good enough performance to get my TombRaider reimplementation running at a good framerate for a console. I even had enough memory to fit the PC game paks into memory at the time. My point is so what if you don't have OpenGL provided by RSX. You can still do a software implementation optimized for Cell. You can do a lot more than you think with what is provided so far.
When I see fanboys like you marked 'Insightful' I fear for young teens learning anything. I wonder what you consider 'real development'. This is one of the few ways you can learn streaming / distributed / realtime development techniques on an embedded system at an affordable price. Have you even read any job requirements lately? People already drool over these skills. If you're not a developer then please don't speak about issues you don't even understand. You should be rated 'Funny'.
Re:PS-3 (Score:4, Insightful)
Why is there x86 support in the kernel? why is there PowerPC support in the kernel?
To make linux run on these systems. Duh.
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-matthew
Re:PS-3 (Score:5, Interesting)
I'm pretty excited about the Cell, and the Playstation is an incredible value for a small form-factor computer that you can put next to your TV without having fan noise be a bother.
Why not support it in the Linux kernel?
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1) Server of what exactly?
2) How's that workin' out for you?
Re:PS-3 (Score:5, Interesting)
2) It's not, yet. It's arriving today via UPS.
And the main reason I bought it was not as a server, although that's certainly a benefit. I'm more interested in development on the Cell.
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The fileserver isn't the only goal, otherwise any random lump of hardware would do.
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I have a rock that makes even less noise than the PS3, maybe it's not too late to cancel the PS3 order- I'll even sell my solution for less.
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First of all, you cannot discount the importance of RAM. For typical server loads, it's dramatically more important than, say, CPU.
Second, the PS3 is a horrible deal in terms of a server. The SPEs, which give it basically all its power, will be virtually unutilized in any typical server context. The Processor is about equivalent to a mid-to-late Pentium III. I/O bandwidth to
Same here (Score:5, Interesting)
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Inquiring minds want to know. Thanks.
Why not? (Score:4, Interesting)
Why would it not be included? If the kernel is still shipping support for 15 year old legacy ISA hardware (yes it is) and Cyrix X86 optimization s(yes it is), it can include support for the PS3, which is likely more in use than either of the above.
There is support for hardware in the kernel that is so obscure that there are probably less than 100 people in the world still using it. There's nothing wrong with this - this is why Open Source beats closed source for overall hardware support - as long as someone is around using it, and someone else maintaining it, there is no reason to remove support for it.
Re:Why not? (Score:5, Informative)
I attended FreedomHEC in Seattle last year. Greg Kroah-Hartman gave a talk, and one point he made was that there are devices supported by the Linux kernel that are literally known to have only one or two users in the whole world; we are talking devices that are so obscure that only one or two people are known to even possess the hardware.
The point he was making is: if you make some hardware, and you are wondering whether your device is too obscure for Linux to accept drivers for it... don't wonder, just submit the drivers.
steveha
Regarding Playstation Support (Score:3, Interesting)
It seems like Cell is probably going to be a lackluster performer, if only the single main processor is used; at that point it's just like using a 3 or 4 year old PowerPC system. But if Linux can support its additional hardware and coprocessors, it seems like you could do some neat stuff with it; I'd think that you could ma
Re:Regarding Playstation Support (Score:4, Informative)
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Re:Regarding Playstation Support (Score:5, Informative)
The hard disk must be PS3-formatted before Linux will see it. Otherwise the hypervisor will not see it and make it available.
BTW:
The hypervisor is a lot like VMWare/Virtual PC/etc. I suspect the Power Processing Elements aren't even fully accessible and that the hypervisor is trapping everything and passing it on as appropriate, like virtualization software you run.
BTW, the virtualization also causes some issues. When I bought a new hard disk for PS3 Linux, it had bad sectors on it (I returned it in the end), but instead of the usual IDE error messages (DriveError) or SCSI errors (with media sense keys), you get nothing, other than a generic "I/O Error reading sector XXXX", which causes the filesystem in use to suddenly go read-only (not sure if ext3 did that or if the hypervisor just disabled the ability to write to the disk - I never had many bad disks with ext3). Basically, you don't even know it's a bad sector as it isn't reported. I suspected it when I could get dd to consistently put the filesystem into read-only mode 16GB in. Another system helped prove the point.
The video hardware is identical - it's virtualized the same way. It's not a driver issue - it's just that Sony has virtualized the video hardware away, and there's no direct access available. Heck, there aren't any WiFi devices accessible either - not for lack of a driver, but that Sony didn't make the WiFi hardware accessible.
Where does the hypervisor live? (Score:5, Interesting)
I don't know about anybody else, but I find this just conceptually fascinating. Where does the hypervisor run from, anyway? Is it in the machine's ROM, so that there's no way to prevent it from booting? (Without irreversible hardware modifications.)
I was just wondering whether it's possible to get rid of it, and boot Linux on the bare metal, or whether the hypervisor is tied into the hardware so tightly, it's impossible to remove and install a new Domain 0 operating system.
Getting Linux to run on the bare metal, 'below' the hypervisor, will be an interesting exercise in what I suspect may be a large part of the future of "unauthorized" computing. I don't think it'll be long before most consumer systems have something like that in place, so it'll be a good intellectual challenge, if nothing else, to see if it can be gotten around.
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Not even that. The USB bus appears to linux to be on top of a PCI bus, which the ps3 does not have.
Re:Regarding Playstation Support (Score:5, Informative)
Cell as implemented in the PS3 has 8 cells. One is disabled (probably due to poor yields when demanding that all 8 be working.) In Linux, one is devoted to kernel tasks. That leaves you with six Cell SPEs to work with besides the PPC PPE.
Well, yes and no. The real problem is that the SPEs are only good for vector data. Anything else requires that you underutilize them. For instance if you have just two numbers and not a whole matrix to multiply, it takes equally long - you just have one useful result and a bunch of useless results that you didn't want. So certain kinds of tasks will be easier to optimize on the SPEs than others. But in many cases you can probably get good results by just using libraries... for instance if libz and libm were accelerated, that would probably make a big difference. Likewise for widget libraries, sound processing libraries, 3d...
3d brings us to the other point, which is that Linux runs in the PS3 "hypervisor" environment and you do not have unfettered access to the video hardware. I don't know precisely what you're not allowed to do that you can do in the commercial environment though; I've never seen a complete description of that.
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Cell as implemented in the PS3 has 8 cells. One is disabled (probably due to poor yields when demanding that all 8 be working.) In Linux, one is devoted to kernel tasks. That leaves you with six Cell SPEs to work with besides the PPC PPE.
You didn't answer the parent's question completely, I think. Which cell is the kernel using (I'm assuming the PPC PPE), and more importantly, does the PS3 support in the Linux kernel enable access to the Six Cell SPEs in anyway, or are you basically on your own.
3d brings us to the other point, which is that Linux runs in the PS3 "hypervisor" environment and you do not have unfettered access to the video hardware. I don't know precisely what you're not allowed to do that you can do in the commercial environment though; I've never seen a complete description of that.
Seems like that defeats the whole purpose doesn't it? PS3 is all about the 3D graphics.
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This paragraph proves that you do not know what we are talking about.
The PowerPC in the "Cell" processor in the PS3 is not, repeat NOT a "Cell". It is known as the PPE, or Primary Processing Element (IIRC.) The actual Cell processors in the PS3 ar
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This paragraph proves that you do not know what we are talking about.
Well, I think that's self-evident, since he's asking a question about it.
The PowerPC in the "Cell" processor in the PS3 is not, repeat NOT a "Cell". It is known as the PPE, or Primary Processing Element (IIRC.) The actual Cell processors in the PS3 are known as the SPEs. I forget what the S stands for, maybe synergistic or something like that. I honestly cannot remember and the information is out there so YOU can look it up :)
The chip in the PS3 has one PPE (a PowerPC with VERY roughly the processing power of a late-model pentium III) and eight SPEs or Cell cores. One of those cores is disabled, probably in order to improve yields. The Linux kernel runs on both the PPE, and ONE of the SPEs. The other six available SPEs are available to the user. Note that all of this information appears in the comment to which you replied, but I am now being more redundant and overusing emphasis in an attempt to get you to actually read it.
If I could offer a couple clarifications (although I'm surely no expert):
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Actually, I am purchasing neither, and someone who is not a complete idiot coward would have noticed that nowhere do I suggest purchasing an Xbox 360. I mention it because I feel that Sony has produced a system useless for running Linux aside from the applications which I
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With the exception of the SPU, most modern hardware spends almost all of it's time on cache misses and branch stalls. The spu however, doesn't have a deep pipeline, or have cache misses, meaning it gets a lot more done than the PPU even while running non-vector math code. Just because you haven't switched up your code to take advantage of vector math optimizations doesn't make it under-utilized, it just means that you skip past the typical bottle-neck and now vector math *may* be your next bottle-neck.
Ho
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But isn't that where hand-optimized assembly really shines ? If you really only have 256kB of RAM, you'll want to forget procedural programming and go with goto's; by hard-coding each variable to a specific memory location can you utilize the tiny memory fully and be absolutely sure there won't be stack overflow.
Each layer of abstraction adds at least a bit overhead, so if resources are tight, str
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Yes, absolutely. Unfortunately hand-optimized code is the opposite of the direction in which programming is going, which is to say, with everything running in virtual machines.
Even today, though, where operating systems and even some programs normally run on the bare metal, we don't typically write very much assembler. Since it is a
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Which makes you wonder why they didn't let Linux's SMP support take over the seven.
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No, it makes you wonder. I know it's for the following reasons:
The Cells are entirely unsuited to general purpose computing. They are only really cap
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Cool thing about the Linux Kernel; it's got drivers for a whole RANGE of things you'll likely never use. But if you do, they're there.
Great, now linux... (Score:4, Funny)
So wait.. (Score:5, Insightful)
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You could also add some remarks about Vista and global climate change, but yeah - basically bar graphs should be enough. Or pie chart. If you really want to troll Slashdot, make them link to Power Point files.
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What the... (Score:5, Informative)
Somebody owes me two minutes. (Score:5, Informative)
Yeah, that was a totally worthwhile read, no?
Let me give everyone else the bottom line, and save you two or three minutes of your life, that you'll otherwise never get back: Now, back to our regularly scheduled Slashvertising....
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Then again I'm sure they made some decent $ out of all the friendly visitors they have to their website now...
ThinkPad? (Score:5, Funny)
He's running kernel benchmarks on a laptop?
Looks like half the things he was measuring were I/O bound? On a laptop?
Phoronix.... more like Moronix.
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But, there were some IO changes. I haven't run the numbers to see if they were statistically significant changes, but tests that show improvements in such a 'poor case' scenario are useful...
Article is vandalised (Score:5, Funny)
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I'm also running through a Squid proxy that blocks all known advertising sites.
What a waste of time (Score:2, Insightful)
Stop the bullshit ads or just shut
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No, I don't think they are. Should they be? Why?
They used games for benchmarking a kernel? (Score:2)
Agree with other posts (Score:2)
Bottom Line (Score:4, Interesting)
It's nice to get features without sacrificing performance. The added PS3 support would nab those ubuntu people to put it on PS3. Not only that, but yellow dog might get some competition if some peoepl decide to make their own PS3-based distro with all kinds of extras.
not newsworthy (Score:4, Insightful)
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A 2% improvement is HUGE (Score:3, Interesting)
Of course the tests probably weren't conducted in a sufficiently scientific way, so the measurement error probably swamps the 2% improvement. If it can be independently repeated, congratulations are definitely in order!
yay, ps3 support! (Score:3, Insightful)
KVM support? (Score:4, Insightful)
Choosing the same acronym for this new technology is only bound to cause confusion.
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Yeah, especially since I can never get my Belkin KVM switch to work properly with Linux, I always lose the mouse or keyboard
I had this problem for years until I decided to finally ditch the Belkin KVM switch. Eventually the trick of switching to the text console and back stopped working, so that was the end of the line for the Belkin KVM.
I doubt it's ever going to be fixed. You can buy a good KVM switch these days for $40, I'd do that.
Even more WOW than Vista! (Score:4, Funny)
Ok...was that sarcastic enough? With this crowd, one can never quite know.
PS3 as MythTV frontend??? (Score:2)
So in other words... (Score:3, Funny)
Unstable I/O? (Score:2)
On 2.6.19-ck1, I ran into a number of show-stopping problems with I/O resulting in several severe hangs (which I never bothered to debug) which I have linked to I/O. I've been hearing reports from other users of the -ck patchset that they are experiencing similar problems with 2.6.20-rc5/6.
I think I'll wait a bit and stick with 2.6.18 for now.
WARNING: DON'T READ THE ARTICLE (Score:4, Funny)
I was suckered in; it looked like a worthy topic. Now, I ask myself: Why did I bother?
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Inline functions (Score:2)
http://lwn.net/Articles/82495/ [lwn.net]
http://lwn.net/Articles/166172/ [lwn.net]
And let me say, LWN [lwn.net] kicks ass.
Lame (Score:3)
-matthew
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A better comparison would be against the kernels in the unpatched Fedora Core 6 and Red Hat Enterprise.
Re:Looks like it got worse!? (Score:5, Informative)
Re:Looks like it got worse!? (Score:4, Insightful)
This isn't to say that there isn't a lot of good stuff in the kernel, but mostly what these benchmarks show is that nothing affecting these particular tasks got broken.
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Erm
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I'd go with a system that spouts pretty fast dual-channel memory and a fast HDD and focus heavily on I/O tests.
Wasn't http://members.optusnet.com.au/ckolivas/interbench
Or http://ck.kolivas.org/kernbench/ [kolivas.org]
I'd rather see interbench scores than FPS.
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I calculated differences in the range of 0.42% to 2.67%
Which in my eye are the same, which is what I would expect.
Also, these tests were on a laptop.
I love benchmarks and all that, but WTF?
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This is an RC by the core kernel team . Once the release is final, you should still interpret it as being "released to the distros" for further testing and stabilization. All critical servers should stick to the kernels provided by their distros, unless they can afford extensive testing
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Re:Isn't it just Microsoft-style "bloat"? (Score:5, Informative)
It's not "bloat" if it's only in the source. Simply put, you don't have to include PS3 support in your binary version. In other words, the only way it affects you is a few extra bytes to download when you want to compile it.
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Re:I disagree! (Score:2)
Actually, that sounds like a g
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I don't think kernel download size will outpace technology (or even the sense of efficiency). In 1993 or even 1998 downloading 40.8MB of source might have been a bit excessive.
Still I find what you are proposing to be intriguing and I wish to s
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You might want to try it sometime as its an educational experiance.
For almost every hardware option you can include whether to build it in, build the module and have the module hooks for it built in or not to include it.
So if you know exactly what hardware you are going to be using you can build a very very small kernel (the theory being it should still be possible to boot a full OS from a floppy, though I haven't tried to do that myself for a while)
If you just want comp
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The Linux model is suprisingly backward for something "Open Source". In a world where customizing things is considered the norm, with drivers it's just plain
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For example, if you actually compile from source, this is undesirable. If you're compiling from source instead of using your distribution's kernel you probably have some specific reason for it, like wanting to apply a patch. Now what if this patch touches some kernel internals (say, the USB subsystem), and updates multiple drivers? Then applying the patch would fail.
Also, having the full source is a VERY go
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That's an interesting question, that I believe will come up more and more in the future as the amount of hardware and drivers increases. For now, I think the main reason for the current model is that it makes things simple for the kernel developers, with a minimal impact on the users-- a few extra megabytes of source code. (Users here being the people who compile their own kernels.)
I personally like this distribution model because i
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Right now you only get frame buffer support so even playing serious Internet games is not really enjoyable. No GPU support yet.
What sane person is going to think that Linux is
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As for the PS3, it's an incredibly fast computer for its price. Of course, it's incredibly hard to program, but we don't do such things because they are easy, right?
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IBM is starting to push out Cell based hardware. That means heavy iron with multiple processors each with multiple types of cores. You know what people are using to learn how to program that? PS3s. You get all the techniques down on a sub $1K chunk of plastic then you migrate those techniques up to $1M+ big iron.
I think if you look at the people contributing to the Cell frameworks & libraries, you're going to find IBM investing heavily in time & lines.
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