From: Huang Ying <ying.huang@linux.intel.com>
To: lkp@lists.01.org
Subject: Re: [mm] c8c06efa8b5: -7.6% unixbench.score
Date: Thu, 08 Jan 2015 16:24:04 +0800 [thread overview]
Message-ID: <1420705444.6201.103.camel@linux.intel.com> (raw)
In-Reply-To: <1420703154.12346.10.camel@stgolabs.net>
[-- Attachment #1: Type: text/plain, Size: 2311 bytes --]
On Wed, 2015-01-07 at 23:45 -0800, Davidlohr Bueso wrote:
> On Thu, 2015-01-08 at 10:27 +0800, Huang Ying wrote:
> Cc'ing Peter.
>
> > FYI, we noticed the below changes on
> >
> > commit c8c06efa8b552608493b7066c234cfa82c47fcea ("mm: convert i_mmap_mutex to rwsem")
>
> Same exact everything, except for the lock type. No sharing going on.
>
> > testbox/testcase/testparams: lituya/unixbench/performance-execl
> >
> > 83cde9e8ba95d180 c8c06efa8b552608493b7066c2
> > ---------------- --------------------------
> > %stddev %change %stddev
> > \ | \
> > 721721 ± 1% +303.6% 2913110 ± 3% unixbench.time.voluntary_context_switches
> > 11767 ± 0% -7.6% 10867 ± 1% unixbench.score
>
> And this workload appears to be from execl, right? Make sense with some
> of those numbers!!
Yes. The test we run for unixbench is execl.
> > 2.323e+08 ± 0% -7.2% 2.157e+08 ± 1% unixbench.time.minor_page_faults
> > 207 ± 0% -7.0% 192 ± 1% unixbench.time.user_time
> > 4923450 ± 0% -5.7% 4641672 ± 0% unixbench.time.involuntary_context_switches
> > 584 ± 0% -5.2% 554 ± 0% unixbench.time.percent_of_cpu_this_job_got
> > 948 ± 0% -4.9% 902 ± 0% unixbench.time.system_time
> > 0 ± 0% +Inf% 672942 ± 2% latency_stats.hits.call_rwsem_down_write_failed.vma_adjust.__split_vma.split_vma.mprotect_fixup.SyS_mprotect.system_call_fastpath
>
> What does this "hits" thing mean exactly? Since I assume both before and
> after runs have the same level of concurrency when pounding on mmap
> operations, I doubt it means that its the amount of calls into the
> slowpath... in addition the lock is obviously contended so we can forget
> about anything in the fastpath.
I think because you changed mutex to rwsem so there was no rwsem related
statistics data for the parent commit.
Best Regards,
Huang, Ying
> So this is a call_rwsem_down_write_failed() vs __mutex_lock_common()
> issue.
>
>
> Thanks,
> Davidlohr
>
> _______________________________________________
> LKP mailing list
> LKP(a)lists.01.org
> https://lists.01.org/mailman/listinfo/lkp
WARNING: multiple messages have this Message-ID (diff)
From: Huang Ying <ying.huang@linux.intel.com>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: LKP ML <lkp@01.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [LKP] [mm] c8c06efa8b5: -7.6% unixbench.score
Date: Thu, 08 Jan 2015 16:24:04 +0800 [thread overview]
Message-ID: <1420705444.6201.103.camel@linux.intel.com> (raw)
In-Reply-To: <1420703154.12346.10.camel@stgolabs.net>
On Wed, 2015-01-07 at 23:45 -0800, Davidlohr Bueso wrote:
> On Thu, 2015-01-08 at 10:27 +0800, Huang Ying wrote:
> Cc'ing Peter.
>
> > FYI, we noticed the below changes on
> >
> > commit c8c06efa8b552608493b7066c234cfa82c47fcea ("mm: convert i_mmap_mutex to rwsem")
>
> Same exact everything, except for the lock type. No sharing going on.
>
> > testbox/testcase/testparams: lituya/unixbench/performance-execl
> >
> > 83cde9e8ba95d180 c8c06efa8b552608493b7066c2
> > ---------------- --------------------------
> > %stddev %change %stddev
> > \ | \
> > 721721 ± 1% +303.6% 2913110 ± 3% unixbench.time.voluntary_context_switches
> > 11767 ± 0% -7.6% 10867 ± 1% unixbench.score
>
> And this workload appears to be from execl, right? Make sense with some
> of those numbers!!
Yes. The test we run for unixbench is execl.
> > 2.323e+08 ± 0% -7.2% 2.157e+08 ± 1% unixbench.time.minor_page_faults
> > 207 ± 0% -7.0% 192 ± 1% unixbench.time.user_time
> > 4923450 ± 0% -5.7% 4641672 ± 0% unixbench.time.involuntary_context_switches
> > 584 ± 0% -5.2% 554 ± 0% unixbench.time.percent_of_cpu_this_job_got
> > 948 ± 0% -4.9% 902 ± 0% unixbench.time.system_time
> > 0 ± 0% +Inf% 672942 ± 2% latency_stats.hits.call_rwsem_down_write_failed.vma_adjust.__split_vma.split_vma.mprotect_fixup.SyS_mprotect.system_call_fastpath
>
> What does this "hits" thing mean exactly? Since I assume both before and
> after runs have the same level of concurrency when pounding on mmap
> operations, I doubt it means that its the amount of calls into the
> slowpath... in addition the lock is obviously contended so we can forget
> about anything in the fastpath.
I think because you changed mutex to rwsem so there was no rwsem related
statistics data for the parent commit.
Best Regards,
Huang, Ying
> So this is a call_rwsem_down_write_failed() vs __mutex_lock_common()
> issue.
>
>
> Thanks,
> Davidlohr
>
> _______________________________________________
> LKP mailing list
> LKP@lists.01.org
> https://lists.01.org/mailman/listinfo/lkp
next prev parent reply other threads:[~2015-01-08 8:24 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-08 2:27 [mm] c8c06efa8b5: -7.6% unixbench.score Huang Ying
2015-01-08 2:27 ` [LKP] " Huang Ying
2015-01-08 7:45 ` Davidlohr Bueso
2015-01-08 7:45 ` [LKP] " Davidlohr Bueso
2015-01-08 7:50 ` Davidlohr Bueso
2015-01-08 7:50 ` [LKP] " Davidlohr Bueso
2015-01-08 8:59 ` Davidlohr Bueso
2015-01-08 8:59 ` [LKP] " Davidlohr Bueso
2015-01-08 10:37 ` Peter Zijlstra
2015-01-08 10:37 ` [LKP] " Peter Zijlstra
2015-01-08 8:24 ` Huang Ying [this message]
2015-01-08 8:24 ` Huang Ying
2015-01-09 2:47 ` Davidlohr Bueso
2015-01-09 2:47 ` [LKP] " Davidlohr Bueso
2015-01-09 3:03 ` Huang Ying
2015-01-09 3:03 ` [LKP] " Huang Ying
2015-01-09 4:02 ` Davidlohr Bueso
2015-01-09 4:02 ` [LKP] " Davidlohr Bueso
2015-01-09 5:41 ` Huang Ying
2015-01-09 5:41 ` [LKP] " Huang Ying
2015-01-10 2:18 ` Davidlohr Bueso
2015-01-10 2:18 ` [LKP] " Davidlohr Bueso
2015-01-27 7:45 ` Huang Ying
2015-01-27 7:45 ` [LKP] " Huang Ying
2015-01-27 20:43 ` Davidlohr Bueso
2015-01-27 20:43 ` [LKP] " Davidlohr Bueso
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