Messages in this thread |  | | | Date | Wed, 4 Oct 2006 09:30:25 -0700 | | From | Andrew Morton <> | | Subject | Re: [PATCH] Fix WARN_ON / WARN_ON_ONCE regression |
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On Wed, 04 Oct 2006 06:21:35 -0700 Tim Chen <tim.c.chen@linux.intel.com> wrote:
> On Tue, 2006-10-03 at 21:39 -0700, Jeremy Fitzhardinge wrote: > > > > > I don't think you've proved your case here. Do you *know* there are > > extra cache misses (ie, measuring them), or is it just your theory to > > explain a performance regression? > > > > I have measured the cache miss with tool. So it is not just my theory. >
And what did that tool tell you?
Guys. Please. Help us out here. None of this makes sense, and it's possible that we have an underlying problem in there which we need to know about.
Please don't just ignore my questions. *why* are we getting a cache miss rate on that integer which is causing measurable performance changes? If we're reading it that frequently then the variable should be in cache(!).
Again: do you know which callsite is causing the problem? I assume one of the ones in softirq.c? Do you know what the cache miss frequency is? etc.
Because if we don't answer these questions there's an excellent chance that the problem (whatever it is) will come back and bite us again. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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