On Wed, May 24, 2006 at 10:23:10AM -0700, Magenheimer, Dan (HP Labs Fort
Collins) wrote:
> At first, I suspected that this degradation was entirely
> due to the fact that large (64MB?) kernel pages were
> now causing many more TLB/VHPT misses because they are
> fragmented into 16KB pages. However, I am
> seeing that domU performance is also reduced by ~3%,
> and domU had this fragmentation prior to VP.
Current the dom0vp model implementation flushes all tlb/vhpt
when granted page is unmapped from dom0.
I think this affects significantly on domU performance.
> Jingke, have you performed the same measurement on domU?
> If so, can you post your results?
>
> Anybody have any other ideas as to what might be
> causing this (major) performance degradation?
For dom0vp model, VHPT size is reduced to 64KBytes to avoid
triggering software lock detection.
For P=M model, its size remain 64MB.
It would be interesting to measure on P=M model with 64KBtyes VHPT size.
(Edit VHPT_SIZE_LOG2 in xen/include/asm-ia64/vhpt.h)
Thanks.
>
> Thanks,
> Dan
>
> ________________________________
>
> From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Zhang,
> Jingke
> Sent: Monday, May 22, 2006 1:49 AM
> To: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-ia64-devel] kernel build performance data with
> dom0_VP modeopen
>
>
>
> Hi all,
>
> I have done kernel build with dom0_vp mode open to
> compare with it close. The specific data as following:
>
> Environment :
>
> Memory:768M
>
> Platform : tiger4
>
> Cpu : Montecito C1 stepping
>
> Compile cmdline : time make >/dev/null 2>&1
>
> Configuration file : @arch/ia64/config/tiger_defconfig
>
>
>
> time
> Real user sys
>
> Cset 10027 (with dom0_vp open): 14m48.377s
> 13m43.960s 0m51.670s
>
> Cset 10022 (with dom0_vp closed): 14m5.752s
> 13m13.200s 0m39.260s
>
> Native :
> 13m55.572s 13m4.366s 0m35.205s
>
> Performance :
>
> Cset 10022: dom0/native =98.7%
>
> Cset 10027:dom0/native=94.1%
>
>
>
> From the result, we can see when dom0_vp mode open, the
> performance of KB has 4.6% degradation.
>
> Thanks
>
> Zhang Jingke
>
>
> _______________________________________________
> Xen-ia64-devel mailing list
> Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-ia64-devel
>
--
yamahata
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