Messages in this thread | | | Subject | Re: [PATCH] sched: recover sched_yield task running time increase | From | "Alex,Shi" <> | Date | Thu, 07 Apr 2011 14:43:16 +0800 |
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On Thu, 2011-04-07 at 14:13 +0800, Rik van Riel wrote: > On 04/06/2011 11:08 PM, Alex,Shi wrote: > > On Wed, 2011-04-06 at 16:04 +0800, Peter Zijlstra wrote: > >> On Wed, 2011-04-06 at 06:33 +0800, Alex Shi wrote: > > >> You do know that any app that relies on sched_yield behaviour is more > >> than broken? Using sched_yield() for anything other than SCHED_FIFO > >> tasks is well outside spec. > >> > >> Furthermore, apparently you used sysctl_sched_compat_yield, which was > >> bound to disappear some time, since with the default settings the yield > >> semantics didn't actually change. > > > > Yes, I used sched_compat_yield, otherwise volano will become extremely > > slow in my single machine testing. We may reconsider our testing > > setting. > > With what JVM is this happening?
I used openjdk from fedora 10~13 and jrockit-R27.3.1-jre1.5.0_11, both of them use sched_yield much. And I just did a quick try with jrockit-R27.4.0-jre1.6.0_02.x86_64, it had same problem.
> > Surely not every JVM uses user space spinlocks and > yield, when we have futexes available?
No, just 7 times futex called in testing, so I think the JVM did not use it. > > >
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