Subject: Re: [linux-audio-dev] Fwd: [PATCH] Preemptive Kernel for Ingo's O(1) scheduler
From: Vincent Touquet (vincent_AT_ulyssis.org)
Date: Sat Jan 12 2002 - 01:12:55 EET
Impressive to say the least :)
Something tells me I'm going to love the upcoming
kernel releases (and certainly 2.6 when it is there).
Lowlatency + native alsa support.
Yummy :)
best regards
vincent
On Fri, Jan 11, 2002 at 10:10:37PM +0100, Roger Larsson wrote:
>Hi low latency lovers,
>
>With the improved throughput in dbench I think this got a better
>chance to be included ... :-)
>
>/RogerL
>
>---------- Forwarded Message ----------
>
>Subject: [PATCH] Preemptive Kernel for Ingo's O(1) scheduler
>Date: 11 Jan 2002 16:04:54 -0500
>From: Robert Love <rml_AT_tech9.net>
>To: linux-kernel_AT_vger.kernel.org
>Cc: kpreempt-tech_AT_lists.sourceforge.net, george_AT_mvista.com, mingo_AT_elte.hu,
>torvalds_AT_transmeta.com
>
>A version of preempt-kernel is now available for Ingo's O(1) scheduler.
>
>For 2.5.2-pre11:
> ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.5/preempt-
>kernel-rml-2.5.2-pre11-1.patch For 2.4.18-pre3 + sched-O1-H6:
> ftp://ftp.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/ingo-O1-
>sched/preempt-kernel-rml-2.4.18-pre3-ingo-1.patch
>
>Because of changes in load_balance, I suggest not using preempt-kernel
>and an additional sched update on 2.5. I'll update as the patches are
>merged into 2.5.
>
>Making the kernel fully preemptible should be synergistic with Ingo's
>scheduler with its faster task dispatch time and better RT support.
>
>Getting the two to play together was not hard, albeit a bit of a pain.
>The actually scheduling support is less, due to the simplified schedule
>and schedule_tail, although there is added code for making the per-CPU
>runqueues preempt-safe.
>
>Benchmarks:
>
>2.5.2-pre11 dbench 16: 24.5364 MB/s
>2.5.2-pre11-preempt dbench 16: 27.5192 MB/s
>
>2.5.2-pre11 latencytest:
>worst-case latency is 18.7ms with 96% scheduling latency on-time
>2.5.2-pre11-preempt latencytest:
>6ms (<1.5ms in all but disk write) with 99.9% scheduling latency on-time
>
>2.5.2-pre11-preempt avg latency is 1.1ms (for an arbitray work-load I
>tested with). The obstacle for sub-ms average latency is still the
>long-held spinlocks that can be 100ms+.
>
>Full ChangeLog:
>
>- make preempt-kernel and Ingo's O(1) scheduler play nicely
>
>- (2.5 only) more include additions
>
>- various cleanups and such
>
>Comments, patches, etc. are appreciated. While it is running stable
>here in both SMP and UP on both 2.4 and 2.5, more testing could reveal
>problems. Also, some optimization could be done at this point to
>hopefully reduce overhead. Enjoy,
>
> Robert Love
>
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo_AT_vger.kernel.org
>More majordomo info at http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at http://www.tux.org/lkml/
>
>-------------------------------------------------------
>
>--
>Roger Larsson
>Skellefteċ
>Sweden
This archive was generated by hypermail 2b28 : Sat Jan 12 2002 - 01:06:05 EET