From: Oleg Nesterov <oleg@redhat.com>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Roland McGrath <roland@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
andi.kleen@intel.com, stable@kernel.org
Subject: Re: [PATCH] Don't apply for write lock on tasklist_lock if parent doesn't ptrace other processes
Date: Fri, 23 Jul 2010 19:34:53 +0200 [thread overview]
Message-ID: <20100723173453.GA29831@redhat.com> (raw)
In-Reply-To: <1279874705.2096.1274.camel@ymzhang.sh.intel.com>
On 07/23, Zhang, Yanmin wrote:
>
> On Thu, 2010-07-22 at 11:05 +0200, Oleg Nesterov wrote:
> > I am not surpized perf blaims tasklist, but I am really surpized this patch
> > adds 10% improvement...
> I changed aim7 workfile to focus on fork/exec and other a couple of sub-cases.
> And this behavior is clear on 8-socket machines.
Thanks...
> After applying my patch (although it's incorrect as there is a race with TRACEME),
> perf shows write_lock_irq in forget_original_parent consumes less than 40% cpu time on
> 8-socket machine.
Any chance you can test the patch I sent? It should have the same effect,
otherwise there is something interesting.
> Is it possible to optimize it to use finer locks instead of the global tasklist_lock?
Heh. We must optimize it. But it is not clear when ;)
Oleg.
next prev parent reply other threads:[~2010-07-23 17:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-15 6:51 [PATCH] Don't apply for write lock on tasklist_lock if parent doesn't ptrace other processes Zhang, Yanmin
2010-07-15 19:53 ` David Rientjes
2010-07-21 21:49 ` Andrew Morton
2010-07-21 22:25 ` Roland McGrath
2010-07-22 9:05 ` Oleg Nesterov
2010-07-22 19:24 ` Roland McGrath
2010-07-23 17:40 ` Oleg Nesterov
2010-07-23 8:45 ` Zhang, Yanmin
2010-07-23 17:34 ` Oleg Nesterov [this message]
2010-07-26 5:05 ` Zhang, Yanmin
2010-07-26 8:53 ` Oleg Nesterov
2010-07-26 9:40 ` Kleen, Andi
2010-07-27 1:15 ` Zhang, Yanmin
2010-07-29 15:12 ` [PATCH] ptrace: optimize exit_ptrace() for the likely case Oleg Nesterov
2010-07-29 17:40 ` Roland McGrath
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