Re: sched_yield: delete sysctl_sched_compat_yield

From: Zhang, Yanmin
Date: Tue Dec 04 2007 - 01:41:51 EST


On Mon, 2007-12-03 at 11:05 +0100, Ingo Molnar wrote:
> * Zhang, Yanmin <yanmin_zhang@xxxxxxxxxxxxxxx> wrote:
>
> > Although no source codes of volanoMark, I suspect it calls
> > Thread.sched. volanoMark is a kind of chatroom benchmark. When a
> > client sends out a message, server will send the message to all
> > clients. I suspect the client calls Thread.yield after sending out a
> > couple of messages.
>
> yeah, so far only volanomark seems to be affected by this, and if it
> indeed calls Thread.yield artificially it's a pretty stupid benchmark
> and it's not the fault of the JDK. If we had the source to volanomark we
> could fix this easily.
>
> > 2 JVM all have regression if sched_compat_yield=0.
> >
> > I ran some testing, such like iozone/specjbb/tbench/dbench/sysbench,
> > and didn't see regression.
>
> which JVM was utilized by the specjbb (Java Business Benchmark) tests?
BEA Jrockit. It supports huge pages which promote performance for about 8%~10%.

-yanmin
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