Re: [Bug #15192] netperf ~50% regression with 2.6.33-rc1, bisectto 1b9508f

From: Lin Ming
Date: Sat Feb 20 2010 - 03:09:58 EST


On Mon, 2010-02-01 at 16:04 +0800, Mike Galbraith wrote:
> On Mon, 2010-02-01 at 01:22 +0100, Rafael J. Wysocki wrote:
> > This message has been generated automatically as a part of a report
> > of recent regressions.
> >
> > The following bug entry is on the current list of known regressions
> > from 2.6.32. Please verify if it still should be listed and let me know
> > (either way).
>
> Yes, it should remain open. We're currently waiting for some data from
> Lin Ming. The regression itself isn't making much sense.. a kernel with
> NEWIDLE disabled should show the same performance, but does not.

(sorry for late response, I'm just back from vacation)

We finally located this to a bug in mwait based C-state entry.
Venki's patch has fixed it.
http://patchwork.kernel.org/patch/78544/

Venki, this is the original report,
http://marc.info/?l=linux-kernel&m=126441481427331&w=4

Thanks,
Lin Ming

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