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From: Juri Lelli <juri.lelli@redhat.com>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>
Subject: Re: help needed in debugging missed wakeup(?)
Date: Mon, 23 Mar 2020 10:27:54 +0100	[thread overview]
Message-ID: <20200323092754.GD14300@localhost.localdomain> (raw)
In-Reply-To: <d8f1b10028b57c5a62bcf3088489c0dbdd0dec5d.camel@pengutronix.de>

Hi,

On 20/03/20 20:04, Lucas Stach wrote:

[...]

> My hope was that someone would could guide me a little with an educated
> guess, to make those trace_printks more helpful. The lockup is hard to
> trigger and there's other unrelated system activity going on, even when
> the relevant user task is stuck, so randomly sprinkling debug
> statements will generate lots of output to filter down.

I'd start by enabling sched:sched_pi_setprio (or adding trace_printks
around there to confirm your suspicion). Once that is confirmed, I'd try
to look at update_curr_dl::throttle and verify if the misbehaving task
was indeed throttled at some point; it shouldn't be, because dl_boosted
flag should be set for it at this point (maybe check this condition as
well).

Best,

Juri


      reply	other threads:[~2020-03-23  9:28 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-20 17:02 help needed in debugging missed wakeup(?) Lucas Stach
2020-03-20 18:06 ` Steven Rostedt
2020-03-20 19:04   ` Lucas Stach
2020-03-23  9:27     ` Juri Lelli [this message]

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