Re: [PATCH 3/3] sched: prefer wakers

[Mike Galbraith]

On Tue, 2008-12-16 at 08:45 +0100, Peter Zijlstra wrote:
> plain text document attachment (wakeup-preempt-fiddle.patch)
> Prefer tasks that wake other tasks to preempt quickly. This improves
> performance because more work is available sooner.
> 
> The workload that prompted this patch was a kernel build over NFS4 (for some
> curious and not understood reason we had to revert commit:
> 18de9735300756e3ca9c361ef58409d8561dfe0d to make any progress at all)
> 
> Without this patch a make -j8 bzImage (of x86-64 defconfig) would take
> 3m30-ish, with this patch we're down to 2m50-ish.

Here, with wimpy 100Mbps nic and my normal config, the improvement is
considerably larger.  Full make -j8 build went from ~6m17s to ~4m28s.

	-Mike

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