From: Yuyang Du <yuyang.du@intel.com>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Byungchul Park <byungchul.park@lge.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Luca Abeni <luca.abeni@unitn.it>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Rik van Riel <riel@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Wanpeng Li <wanpeng.li@hotmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: Re: [RFC][PATCH 5/5] sched/core: Add debug code to catch missing update_rq_clock()
Date: Sun, 15 May 2016 10:14:39 +0800 [thread overview]
Message-ID: <20160515021439.GC8790@intel.com> (raw)
In-Reply-To: <1463082593-27777-6-git-send-email-matt@codeblueprint.co.uk>
Hi Matt,
Thanks for Ccing me.
I am indeed interested, because I recently encountered an rq clock
issue, which is that the clock jumps about 200ms when I was
experimenting the "flat util hierarchy" patches, which really annoyed
me, and I had to stop to figure out what is wrong (but haven't yet
figured out ;))
First, this patchset does not solve my problem, but never mind, by
reviewing your patches, I have some comments:
On Thu, May 12, 2016 at 08:49:53PM +0100, Matt Fleming wrote:
>
> - rq->clock_skip_update = 0;
> + /* Clear ACT, preserve everything else */
> + rq->clock_update_flags ^= RQCF_ACT_SKIP;
The comment says "Clear ACT", but this is really xor, and I am not sure
this is even what you want.
In addition, would it be simpler to do this?
update_rq_clock()
if (flags & RQCF_ACT_SKIP)
flags <<= 1; /* effective skip is an update */
return;
flags = RQCF_UPDATED;
Thanks,
Yuyang
next prev parent reply other threads:[~2016-05-15 10:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-12 19:49 [RFC][PATCH 0/5] sched: Diagnostic checks for missing rq clock updates Matt Fleming
2016-05-12 19:49 ` [RFC][PATCH 1/5] sched/fair: Update the rq clock before detaching tasks Matt Fleming
2016-05-12 19:49 ` [RFC][PATCH 2/5] sched: Add wrappers for lockdep_(un)pin_lock() Matt Fleming
2016-05-12 19:49 ` [RFC][PATCH 3/5] sched/core: Reset RQCF_ACT_SKIP before unpinning rq->lock Matt Fleming
2016-05-12 19:49 ` [RFC][PATCH 4/5] sched/fair: Push rq lock pin/unpin into idle_balance() Matt Fleming
2016-05-12 19:49 ` [RFC][PATCH 5/5] sched/core: Add debug code to catch missing update_rq_clock() Matt Fleming
2016-05-15 2:14 ` Yuyang Du [this message]
2016-05-16 9:46 ` Matt Fleming
2016-05-16 20:11 ` Yuyang Du
2016-05-17 12:24 ` Matt Fleming
2016-05-17 19:01 ` Yuyang Du
2016-05-18 8:41 ` Matt Fleming
2016-05-18 22:51 ` Yuyang Du
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