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 <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Cc: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED], 
>[EMAIL PROTECTED]
>
>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
>
>-
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>-------------------------------------------------------
>
>-- 
>Roger Larsson
>Skellefte�
>Sweden

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