Anticipatory Scheduler in Kernel 2.5+ Benchmarked

gmuslera points to this article at KernelTrap comparing available benchmarks for schedulers available for the 2.5 kernel, with the 2.4's scheduler as a reference poin. "In some cases, the new Anticipatory Scheduler performs several times better than the others, doing a task in a few seconds instead minutes like the others."

Comments

I've tried it and it rocks

[huhmz]

I have a multithreaded perl app (yes perl has descent thread support in 5.6 and later) which does a lot of mixed write/read I/O to and from a database. With 2.4 and 40 threads I can hardly use the system (of course I dont have to abuse my computer with 80 threads but Im trying to prove a point here).
Switching to a new tabbed terminal in fluxbox it takes ages to redraw and switching between virtual desktops is an act of futility.
With 2.5 It get good interactive performance and don't see this effect much at all. For sure this is also a bit due to the new VM code.
Of course I would probably get the best interactivity with the SFQ scheduler but thats secondary in this case. At least xmms doesn't skip with this during very heavy I/O. I do not use the new NPTL code which would help further I suppose.

Re:Anti-slashdotting?

[Jahf]

Mozilla's Bugzilla does this now.

Perhaps one better ... redirect all /. requests to a Google-cache of your webpage (assuming you're lucky enough to have the page cached before someone notices).

Ok.. I'll bite... what's a Scheduler?

[!Xabbu]

What does it do for kernel performance? Or does it do anything for performance? ...I haven't run Linux on a desktop for almost a year. It hurts mommy.. please make the bad man go away!

Re:It's about time...

[ottffssent]

I know that's Score:5 Funny but there's a serious note here.

If a site is down, Mozilla could pretty easily grab the google cache instead. Or, if there's no google cache or if the cache matches the current page, check archive.org. Mozilla could auto-generate a page offering the user some options. Think about it - it would be the end of 404 errors. Instead of

404 The requested page could not be found.

you could get

The site you requested is currently down. Would you like to use Google's cache instead? I also have a snapshot of the page you requested from August 12, 2002 but older ones are available here.

Re:Great!

[CoolVibe]

I'd love to try 2.5, but the closed nvidia drivers is the only thing that's keeping me grounded to 2.4.

Although I _suspect_ they will run fine on 2.5, I don't want to risk it. It's still a little too bleeding edge for me. They call it bleeding edge for a reason, because you _will_ bleed and get hurt from time to time.

I guess I am a big fat ninny when it comes to bleeding edge stuff (although I do lust for all the new toys, the waiting just increases my contentness when such cool stuff gets part of stable stuff) :-)

Speaking of avoiding the bleeding edge, it would be sooo cool if this IO scheduler was backported to 2.4.

WOW CS 162 Lecture

[vandel405]

I'm currently enrolled in cs 162 (OSs) at UC Berkeley, todays lecture was on different flavors of schedulers and this scheduler was mentioned breifly. For more theoretical info see http://webcast.berkeley.edu/courses/archive.html?p rog=116&group=52 for a webcast of the lecture or http://inst.eecs.berkeley.edu/~cs162/Lectures/L11. pdf for a pdf of the lecutre notes.

Re:Finally

[psamuels]

Windows simply handles multithreading better.

Nah, it handles certain start-up costs for complex applications better. This may or may not have anything to do with multithreading per se.

And you can tell the I/O is crap just by looking at KDE's performance when compared to Win2k. Windows just flies.

I don't run KDE, but I understand that it has had speed issues in the past because it uses a lot of interconnected C++ shared libraries, which really tax the dynamic loader. The Windows link scheme, by the way, is much more primitive (read: fast at runtime). Microsoft also uses a hack (disk layout profiling) to speed up load time further. (Not that "hack" is necessarily a bad thing - after all it does get the job done.)

A couple of years ago, Jakub Jelinek came up with a utility similar to IRIX Quickstart for ELF binaries / libraries, which does "prelinking" to dramatically reduce relocation overhead at runtime in the common cases (without sacrificing flexibility, for the uncommon cases). A side effect is reducing memory usage due to COW. I never heard what happened to that project - anyone know if it is considered production-quality yet, or if binutils / glibc will be shipping it any time soon? Apparently it helped KDE quite a bit.