Re: [RFC PATCH] sched/eevdf: Return leftmost entity in pick_eevdf() if no eligible entity is found

From: Peter Zijlstra <peterz@infradead.org>
To: Chen Yu <yu.c.chen@intel.com>
Cc: Xuewen Yan <xuewen.yan94@gmail.com>,
	Abel Wu <wuyun.abel@bytedance.com>,
	Ingo Molnar <mingo@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Tim Chen <tim.c.chen@intel.com>,
	Tiwei Bie <tiwei.btw@antgroup.com>,
	Honglei Wang <wanghonglei@didichuxing.com>,
	Aaron Lu <aaron.lu@intel.com>, Chen Yu <yu.chen.surf@gmail.com>,
	Yujie Liu <yujie.liu@intel.com>,
	linux-kernel@vger.kernel.org,
	kernel test robot <oliver.sang@intel.com>,
	Tianchen Ding <dtcccc@linux.alibaba.com>
Subject: Re: [RFC PATCH] sched/eevdf: Return leftmost entity in pick_eevdf() if no eligible entity is found
Date: Fri, 19 Apr 2024 18:24:28 +0200	[thread overview]
Message-ID: <20240419162428.GB23130@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <ZiJBqRafMdBi+wCV@chenyu5-mobl2>

On Fri, Apr 19, 2024 at 06:04:25PM +0800, Chen Yu wrote:

> > Also, could you put a few words in on how often these clips are hit? I
> > suspect it's fairly rare (but crucial when it does).
> 
> Everytime it happens a subsequent NULL pointer exception usually happens.
> The trace data was posted here: 

That was not the question. Suppose I put a printk whenever the clamp()
actually changes the value, do I get a stormflood of output, or do I get
a sporadic blip.