From: David Singleton <dsingleton@mvista.com>
To: dino@in.ibm.com
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: Perf degradation from -rt14 onwards
Date: Thu, 01 Dec 2005 12:59:44 -0800 [thread overview]
Message-ID: <438F6440.2010409@mvista.com> (raw)
In-Reply-To: <20051201204227.GA16035@in.ibm.com>
Dinakar Guniguntala wrote:
>I was wondering why the following change was made from -rt14
>onwards.
>
>
>@@ -1634,7 +1531,7 @@ asmlinkage long sys_futex(u32 __user *ua
> int val3)
> {
> struct timespec t;
>- unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
>+ unsigned long timeout = 0;
>
>This was introduced in patch-2.6.14-rt13-rf3 by David.
>
>This seems to return spurious -ETIMEDOUT errors even in the
>non-robust code and results in userspace (glibc) retrying
>several mutex operations before it succeeds. I was chasing
>down a degradation of performance of some testcases and was
>able to fix those by reverting this change back.
>
>
Yes. The default timeout should be set to MAX_SCHEDULE_TIMEOUT, not zero.
David
> -Dinakar
>
>
>
next prev parent reply other threads:[~2005-12-01 20:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-01 20:42 Perf degradation from -rt14 onwards Dinakar Guniguntala
2005-12-01 20:59 ` David Singleton [this message]
2005-12-01 21:21 ` Ingo Molnar
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