Messages in this thread | | | From | "Pallipadi, Venkatesh" <> | Date | Thu, 30 Oct 2008 17:32:21 -0700 | Subject | RE: cpu2000(both float and int) 13% regression with 2.6.28-rc1 |
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>-----Original Message----- >From: linux-kernel-owner@vger.kernel.org >[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Suresh Siddha >Sent: Tuesday, October 28, 2008 1:27 PM >To: Ingo Molnar >Cc: Zhang, Yanmin; LKML; H. Peter Anvin; Siddha, Suresh B; >Roland McGrath; Hiroshi Shimamoto; Yinghai Lu >Subject: Re: cpu2000(both float and int) 13% regression with 2.6.28-rc1 > >On Tue, Oct 28, 2008 at 01:03:27AM -0700, Ingo Molnar wrote: >> >> * Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote: >> >> > Comparing with 2.6.27, cpu2000 (both float and int) has >about 13% regression >> > with 2.6.28-rc1 on my new-model x86-64 machine. >> > >> > I bisected down to below patch. >> > >> > commit 0afe2db21394820d32646a695eccf3fbfe6ab5c7 >> > Merge: d847059... 43603c8... >> > Author: Ingo Molnar <mingo@elte.hu> >> > Date: Sat Oct 11 20:23:20 2008 +0200 >> > >> > Merge branch 'x86/unify-cpu-detect' into >x86-v28-for-linus-phase4-D >> > >> > Conflicts: >> > arch/x86/kernel/cpu/common.c >> > arch/x86/kernel/signal_64.c >> > include/asm-x86/cpufeature.h >> > >> > >> > When I tried to revert it against 2.6.28-rc2, there are >many conflictions. > >Ingo, I will work with Yanmin and report our findings. It is >interesting to see >double digit regression on cpu2000 benchmark. My understanding is that >these benchmarks are not sensitive to signal handling. Also lmbench >signal handling(lat_sig) has less than 3-4% regression, because of >added overhead duing signal setup and restore. Context switch >didn't have >any noticeable difference, when I measure before. >
We figured out that this is not related to signals. But to this mismerge here
> +#define X86_FEATURE_AMDC1E (3*32+21) /* AMD C1E detected */ > + #define X86_FEATURE_XTOPOLOGY (3*32+21) /* cpu topology enum extensions */
I had earler sent a patch to fix this. http://marc.info/?l=linux-kernel&m=122341178202930&w=2
But, somehow I don’t see this patch either in Linus's git or in tip.
ingo, hpa: Can you push that patch along.
Thanks, Venki
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