Date: Fri, 17 Feb 2012 19:03:20 +0200 From: Alexander Motin <mav@FreeBSD.org> To: Arnaud Lacombe <lacombar@gmail.com> Cc: freebsd-hackers@freebsd.org, Florian Smeets <flo@freebsd.org>, Jeff Roberson <jroberson@jroberson.net>, Andriy Gapon <avg@freebsd.org>, FreeBSD current <freebsd-current@freebsd.org> Subject: Re: [RFT][patch] Scheduling for HTT and not only Message-ID: <4F3E8858.4000001@FreeBSD.org> In-Reply-To: <CACqU3MWEC4YYguPQF_d%2B_i_CwTc=86hG%2BPbxFgJQiUS-=AHiRw@mail.gmail.com> References: <4F2F7B7F.40508@FreeBSD.org> <4F366E8F.9060207@FreeBSD.org> <4F367965.6000602@FreeBSD.org> <4F396B24.5090602@FreeBSD.org> <alpine.BSF.2.00.1202131012270.2020@desktop> <4F3978BC.6090608@FreeBSD.org> <alpine.BSF.2.00.1202131108460.2020@desktop> <4F3990EA.1080002@FreeBSD.org> <4F3C0BB9.6050101@FreeBSD.org> <alpine.BSF.2.00.1202150949480.2020@desktop> <4F3E807A.60103@FreeBSD.org> <CACqU3MWEC4YYguPQF_d%2B_i_CwTc=86hG%2BPbxFgJQiUS-=AHiRw@mail.gmail.com>
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On 17.02.2012 18:53, Arnaud Lacombe wrote: > On Fri, Feb 17, 2012 at 11:29 AM, Alexander Motin<mav@freebsd.org> wrote: >> On 02/15/12 21:54, Jeff Roberson wrote: >>> On Wed, 15 Feb 2012, Alexander Motin wrote: >>>> I've decided to stop those cache black magic practices and focus on >>>> things that really exist in this world -- SMT and CPU load. I've >>>> dropped most of cache related things from the patch and made the rest >>>> of things more strict and predictable: >>>> http://people.freebsd.org/~mav/sched.htt34.patch >>> >>> This looks great. I think there is value in considering the other >>> approach further but I would like to do this part first. It would be >>> nice to also add priority as a greater influence in the load balancing >>> as well. >> >> I haven't got good idea yet about balancing priorities, but I've rewritten >> balancer itself. As soon as sched_lowest() / sched_highest() are more >> intelligent now, they allowed to remove topology traversing from the >> balancer itself. That should fix double-swapping problem, allow to keep some >> affinity while moving threads and make balancing more fair. I did number of >> tests running 4, 8, 9 and 16 CPU-bound threads on 8 CPUs. With 4, 8 and 16 >> threads everything is stationary as it should. With 9 threads I see regular >> and random load move between all 8 CPUs. Measurements on 5 minutes run show >> deviation of only about 5 seconds. It is the same deviation as I see caused >> by only scheduling of 16 threads on 8 cores without any balancing needed at >> all. So I believe this code works as it should. >> >> Here is the patch: http://people.freebsd.org/~mav/sched.htt40.patch >> >> I plan this to be a final patch of this series (more to come :)) and if >> there will be no problems or objections, I am going to commit it (except >> some debugging KTRs) in about ten days. So now it's a good time for reviews >> and testing. :) >> > is there a place where all the patches are available ? All my scheduler patches are cumulative, so all you need is only the last mentioned here sched.htt40.patch. But in some cases, especially for multi-socket systems, to let it show its best, you may want to apply additional patch from avg@ to better detect CPU topology: https://gitorious.org/~avg/freebsd/avgbsd/commit/6bca4a2e4854ea3fc275946a023db65c483cb9dd > I intend to run > some tests on a 1x2x2 (atom D510), 1x4x1 (core-2 quad), and eventually > a 2x8x2 platforms, against r231573. Results should hopefully be > available by the end of the week-end/middle of next week[0]. > > [0]: the D510 will likely be testing a couple of Linux kernel over the > week-end, and a FreeBSD run takes about 2.5 days to complete. -- Alexander Motin
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