Re: Latency tests with 2.6.12-rc1

Lee Revell
2005-03-19T07:51:46Z

On Sat, 2005-03-19 at 08:08 +0100, Ingo Molnar wrote:
> 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@veritas.com
>
> [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?

As a matter of fact the ext3 latencies do not appear to be causing
problems, at least not at those settings, even with data=ordered.

It's impossible to tell much more because the mainline kernel lacks the
instrumentation that the realtime patchset provides.

Lee