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Linux 2.6.20-rc6 Kernel Performance
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."
So the bottom line here is that they're almost exactly the same?
In the land of the blind, the one-eyed man is kinky.
I think that means that it is bootable on a PS3. This kind of thing would only be included if it was compiled for a PS3, and as for "is it required", only if you want to run arbitrary distros on a PS3, which there are people who'd want to do that.
34486853790
Connection too slow for X forwarding? Try "ssh -CX user@host"
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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7SPE's are accessible via Linux, as long as you use the Cell BBE SDK..
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.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Did you only skip to the last page? If you looked over every benchmark, the new kernel had improved performance in almost every test, save for two of the last three.
http://blindscribblings.com - Tasty pop-culture in conceptual fashion.
You misunderstand the Linux kernel ethos. The idea is to include *everything* "in the kernel", but you only have to compile the parts that you want. That way there is a central place to track all changes and maintain compatibility and consistency between all parts of the kernel, without having to set an internal interfaces in stone.
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.
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.
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.
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
lf(1): it's like ls(1) but sorts filenames by extension, tersely