From: Waiman Long <waiman.long@hp.com>
To: John Stoffel <john@stoffel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>
Subject: Re: [PATCH] dcache: Translating dentry into pathname without taking rename_lock
Date: Wed, 04 Sep 2013 22:04:31 -0400 [thread overview]
Message-ID: <5227E6AF.2040603@hp.com> (raw)
In-Reply-To: <21031.39606.16374.72229@quad.stoffel.home>
On 09/04/2013 04:40 PM, John Stoffel wrote:
>>>>>> "Waiman" == Waiman Long<waiman.long@hp.com> writes:
> Waiman> In term of AIM7 performance, this patch has a performance boost of
> Waiman> about 6-7% on top of Linus' lockref patch on a 8-socket 80-core DL980.
>
> Waiman> User Range | 10-100 | 200-10000 | 1100-2000 |
> Waiman> Mean JPM w/o patch | 4,365,114 | 7,211,115 | 6,964,439 |
> Waiman> Mean JPM with patch | 3,872,850 | 7,655,958 | 7,422,598 |
> Waiman> % Change | -11.3% | +6.2% | +6.6% |
>
> This -11% impact is worisome to me, because at smaller numbers of
> users, I would still expect the performance to go up. So why the big
> drop?
>
> Also, how is the impact of these changes on smaller 1 socket, 4 core
> systems? Just because it helps a couple of big boxes, doesn't mean it
> won't hurt the more common small case.
>
> John
I don't believe the patch will make it slower with less user. It is more
a result of run-to-run variation. The short workload typically completed
in a very short time. In the 10-100 user range, the completion times
range from 0.02-0.11s. With a higher user count, it needs several
seconds to run and hence the results are more reliable.
Longman
next prev parent reply other threads:[~2013-09-05 2:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-04 19:05 [PATCH] dcache: Translating dentry into pathname without taking rename_lock Waiman Long
2013-09-04 19:11 ` Al Viro
2013-09-04 19:33 ` Waiman Long
2013-09-04 19:43 ` Al Viro
2013-09-05 1:55 ` Waiman Long
2013-09-05 2:42 ` Al Viro
[not found] ` <CA+55aFwW+hWwQd8+NgukSidHbf2bnd6QO0yKK9NAgX+9rt0cOQ@mail.gmail.com>
[not found] ` <5227E321.4090008@hp.com>
2013-09-05 2:48 ` Linus Torvalds
2013-09-05 4:20 ` Al Viro
2013-09-04 19:26 ` Waiman Long
2013-09-04 20:40 ` John Stoffel
2013-09-05 2:04 ` Waiman Long [this message]
2013-09-05 13:29 ` John Stoffel
2013-09-05 17:28 ` Waiman Long
2013-09-04 21:31 ` Linus Torvalds
2013-09-05 2:17 ` Waiman Long
-- strict thread matches above, loose matches on Subject: below --
2013-09-05 4:30 George Spelvin
2013-09-05 17:06 ` Waiman Long
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