From: Dipankar Sarma <dipankar@in.ibm.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Andrew Morton <akpm@osdl.org>,
paulmck@us.ibm.com, torvalds@osdl.org,
linux-kernel@vger.kernel.org, nickpiggin@yahoo.com.au,
hch@infradead.org
Subject: Re: [patch 2/2] fix file counting
Date: Wed, 1 Feb 2006 01:49:16 +0530 [thread overview]
Message-ID: <20060131201916.GB5633@in.ibm.com> (raw)
In-Reply-To: <43DF3D0D.6080409@cosmosbay.com>
On Tue, Jan 31, 2006 at 11:33:49AM +0100, Eric Dumazet wrote:
> Dipankar Sarma a écrit :
> >>Putting an atomic op into the file_free path?
> >
> >Here are some numbers from a 32-way (HT) P4 xeon box with kernbench -
> >
>
> Hi Dipankar, thank you very much for doing these tests.
>
> To have an idea of the number of files that are allocated/freed during a
> kernel build, I added 4 fields in struct files_stat.
>
> # cat /proc/sys/fs/file-nr
> 153 0 206071 153 755767 755620 5119
>
> So thats (755767-39169)/(4*60+56) = 2420 files opened per second.
>
> Number of changes on central atomic_t was :
> (5119-1131)/(4*60+56) = 13 per second.
>
> 13 atomic ops per second (instead of 2420*2 per second if I had one
> atomic_t as in your patch), this is certainly not something we can notice
> in a typical SMP machine... maybe on a big NUMA machine it could be
> different ?
Depends on what you call big :) The one I ran on is a 2-node NUMA
16(32)-way with HT. I can't find anything bigger than this
in our server farm. On a 8-way ppc64 box too, there was no difference
at all.
Can you think of some non-microbenchish workload with more open/sec ?
I privately pointed out this thread to John Hawkes from SGI to see
if they care about the potential issues. In the mean while,
I will investigate some more.
Thanks
Dipankar
next prev parent reply other threads:[~2006-01-31 20:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-26 18:40 [patch 0/2] RCU: fix various latency/oom issues Dipankar Sarma
2006-01-26 18:41 ` [patch 1/2] rcu batch tuning Dipankar Sarma
2006-01-26 18:42 ` [patch 2/2] fix file counting Dipankar Sarma
2006-01-26 20:15 ` Eric Dumazet
2006-01-27 22:54 ` Andrew Morton
2006-01-27 23:14 ` Paul E. McKenney
2006-01-27 23:28 ` Andrew Morton
2006-01-28 18:42 ` Dipankar Sarma
2006-01-28 18:51 ` Andrew Morton
2006-01-28 19:10 ` Dipankar Sarma
2006-01-30 17:00 ` Dipankar Sarma
2006-01-31 10:33 ` Eric Dumazet
2006-01-31 20:19 ` Dipankar Sarma [this message]
2006-01-26 19:33 ` [patch 1/2] rcu batch tuning Paul E. McKenney
2006-01-26 19:42 ` Dipankar Sarma
2006-02-17 15:41 [PATCH 0/2] RCU updates Dipankar Sarma
2006-02-17 15:43 ` [PATCH 1/2] rcu batch tuning Dipankar Sarma
2006-02-17 15:46 ` [PATCH 2/2] fix file counting Dipankar Sarma
2006-02-18 9:04 ` Andrew Morton
2006-02-18 9:25 ` Dipankar Sarma
2006-02-18 9:45 ` Andrew Morton
2006-02-18 10:06 ` Dipankar Sarma
2006-02-18 10:10 ` Andrew Morton
2006-02-18 10:44 ` Dipankar Sarma
2006-02-18 12:14 ` Christoph Hellwig
2006-02-18 12:31 ` Arjan van de Ven
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20060131201916.GB5633@in.ibm.com \
--to=dipankar@in.ibm.com \
--cc=akpm@osdl.org \
--cc=dada1@cosmosbay.com \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nickpiggin@yahoo.com.au \
--cc=paulmck@us.ibm.com \
--cc=torvalds@osdl.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).