Re: Latency tests with 2.6.12-rc1

[Ingo Molnar]

* Lee Revell <rlrevell@xxxxxxxxxxx> wrote:

> I did the same quick latency tests with 2.6.12-rc1 that I posted about
> for 2.6.11 a few weeks ago.
> 
> 2.6.12-rc1 is significantly better than 2.6.11.  Running JACK at 64
> frames (1.3 ms) works very well.  I was not able to produce xruns even
> with "dbench 64", which slows the system to a crawl.  With 2.6.11, I
> could easily produce xruns with much lighter loads.
> 
> It would appear that the latency issues related to the 4 level page
> tables merge have been resolved.

great! The change in question is most likely the copy_page_range() fix
that Hugh resurrected:

ChangeSet 1.2037, 2005/03/08 09:26:46-08:00, hugh@xxxxxxxxxxx

	[PATCH] copy_pte_range latency fix
	
	Ingo's patch to reduce scheduling latencies, by checking for lockbreak in
	copy_page_range, was in the -VP and -mm patchsets some months ago; but got
	preempted by the 4level rework, and not reinstated since. Restore it now
	in copy_pte_range - which mercifully makes it easier.

are the ext3 related latencies are gone as well - or are you working it
around by not using data=ordered?

    Ingo
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