linux-kernel - Re: sched_yield: delete sysctl_sched_compat

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Date:	Mon, 3 Dec 2007 11:05:54 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Cc:	Nick Piggin <nickpiggin@...oo.com.au>,
	Arjan van de Ven <arjan@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: sched_yield: delete sysctl_sched_compat_yield


* Zhang, Yanmin <yanmin_zhang@...ux.intel.com> 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?

	Ingo
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