From: Mike Galbraith <efault@gmx.de>
To: Thomas Pilarski <thomas.pi@arcor.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>,
Gregory Haskins <ghaskins@novell.com>,
bugme-daemon@bugzilla.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores
Date: Mon, 02 Feb 2009 09:52:11 +0100 [thread overview]
Message-ID: <1233564731.21378.9.camel@marge.simson.net> (raw)
In-Reply-To: <1233563600.3669.36.camel@localhost.localdomain>
On Mon, 2009-02-02 at 09:33 +0100, Thomas Pilarski wrote:
> Am Montag, den 02.02.2009, 09:19 +0100 schrieb Peter Zijlstra:
> > I suppose you'll have to go bug the glibc people about their random()
> > implementation.
>
> Yes, I will.
Finding the below was easy enough...
/* POSIX.1c requires that there is mutual exclusion for the `rand' and
`srand' functions to prevent concurrent calls from modifying common
data. */
__libc_lock_define_initialized (static, lock)
...
long int
__random ()
{
int32_t retval;
__libc_lock_lock (lock);
(void) __random_r (&unsafe_state, &retval);
__libc_lock_unlock (lock);
return retval;
}
...but finding the plumbing leading to __lll_lock_wait_private()
over-taxed my attention span.
-Mike
next prev parent reply other threads:[~2009-02-02 8:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-12562-10286@http.bugzilla.kernel.org/>
2009-01-28 20:56 ` [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores Andrew Morton
2009-01-28 22:15 ` Peter Zijlstra
2009-01-28 22:25 ` Thomas Pilarski
2009-01-29 9:07 ` Peter Zijlstra
2009-01-29 10:12 ` Thomas Pilarski
2009-01-29 10:24 ` Thomas Pilarski
2009-01-29 10:31 ` Peter Zijlstra
2009-01-29 11:37 ` Peter Zijlstra
2009-01-29 14:05 ` Thomas Pilarski
2009-01-30 7:57 ` Mike Galbraith
2009-02-02 7:43 ` Thomas Pilarski
2009-02-02 8:19 ` Peter Zijlstra
2009-02-02 8:33 ` Thomas Pilarski
2009-02-02 8:52 ` Mike Galbraith [this message]
2009-02-02 8:55 ` Peter Zijlstra
2009-02-02 12:15 ` Peter Zijlstra
2009-02-02 18:29 ` Michael Kerrisk
2009-02-02 18:35 ` Peter Zijlstra
2009-02-03 4:55 ` Mike Galbraith
2009-02-03 3:56 ` Valdis.Kletnieks
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