Messages in this thread | | | Date | Thu, 01 Dec 2005 12:59:44 -0800 | From | David Singleton <> | Subject | Re: Perf degradation from -rt14 onwards |
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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 > > >
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