From: ebiederm@xmission.com (Eric W. Biederman)
To: Robin Holt <holt@sgi.com>
Cc: linux-kernel@vger.kernel.org, Pavel Emelyanov <xemul@openvz.org>,
Oleg Nesterov <oleg@tv-sign.ru>,
Sukadev Bhattiprolu <sukadev@us.ibm.com>,
Paul Menage <menage@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Patch] Scale pidhash_shift/pidhash_size up based on num_possible_cpus().
Date: Thu, 31 Jul 2008 15:04:56 -0700 [thread overview]
Message-ID: <m1bq0d1zhz.fsf@frodo.ebiederm.org> (raw)
In-Reply-To: <20080731200835.GK9663@sgi.com> (Robin Holt's message of "Thu, 31 Jul 2008 15:08:35 -0500")
Robin Holt <holt@sgi.com> writes:
> Like so???
>
> I have not tested this yet.
Looks reasonable to me.
In what circumstances was the lookup in the pid hash table with
long changes causing a performance slowdown?. We don't perform
a lot of lookups.
> - pidhash_shift = min(12, pidhash_shift);
> + pidhash_shift = min(fls(PID_MAX_LIMIT) - 6, pidhash_shift);
> pidhash_size = 1 << pidhash_shift;
next prev parent reply other threads:[~2008-07-31 22:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-31 17:00 [Patch] Scale pidhash_shift/pidhash_size up based on num_possible_cpus() Robin Holt
2008-07-31 18:35 ` Eric W. Biederman
2008-07-31 19:32 ` Robin Holt
2008-07-31 19:49 ` Eric W. Biederman
2008-07-31 20:08 ` Robin Holt
2008-07-31 22:04 ` Eric W. Biederman [this message]
2008-08-01 12:04 ` Robin Holt
2008-08-01 18:27 ` Eric W. Biederman
2008-08-01 19:13 ` Robin Holt
2008-08-01 19:59 ` Eric W. Biederman
2008-08-04 13:11 ` Stephen Champion
2008-08-04 20:36 ` Eric W. Biederman
2008-08-04 23:58 ` Robin Holt
2008-08-05 0:38 ` Eric W. Biederman
2008-08-06 3:21 ` Stephen Champion
2008-08-01 18:49 ` Linus Torvalds
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