linux-kernel - Re: [PATCH] sched: fix cpu utilization account error

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Date:	Tue, 02 Jul 2013 05:07:54 +0200
From:	Mike Galbraith <efault@....de>
To:	Xie XiuQi <xiexiuqi@...wei.com>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	stable@...r.kernel.org, Li Zefan <lizefan@...wei.com>,
	Zhang Hang <bob.zhanghang@...wei.com>,
	Li Bin <huawei.libin@...wei.com>
Subject: Re: [PATCH] sched: fix cpu utilization account error

On Mon, 2013-07-01 at 19:26 +0800, Xie XiuQi wrote:

> Here is the kthread main logic. Although it's not a good idea, but it does
> exist:

Why not fix this instead?

> while (!kthread_should_stop()) {
> 	/* call schedule every 1 sec */
> 	if (HZ <= jiffies - last) {
> 		last = jiffies;
> 		schedule();
> 	}

Hanging out in the kernel for ages is not cool.  That doesn't mean
something else might not pop up that forces the issue, but to date it
has not, and sacrificing precious fastpath cycles is not attractive.

-Mike

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