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From: Mike Galbraith <efault@gmx.de>
To: Mel Gorman <mgorman@techsingularity.net>,
	Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	ulf.hansson@linaro.org, broonie@kernel.org,
	lee.tibbert@gmail.com, oleksandr@natalenko.name
Subject: Re: [PATCH BUGFIX/IMPROVEMENT V2 0/3] three bfq fixes restoring service guarantees with random sync writes in bg
Date: Thu, 31 Aug 2017 19:06:06 +0200	[thread overview]
Message-ID: <1504199166.666.11.camel@gmx.de> (raw)
In-Reply-To: <20170831144257.oa5nm6vzihpam6kw@techsingularity.net>

On Thu, 2017-08-31 at 15:42 +0100, Mel Gorman wrote:
> On Thu, Aug 31, 2017 at 08:46:28AM +0200, Paolo Valente wrote:
> > [SECOND TAKE, with just the name of one of the tester fixed]
> > 
> > Hi,
> > while testing the read-write unfairness issues reported by Mel, I
> > found BFQ failing to guarantee good responsiveness against heavy
> > random sync writes in the background, i.e., multiple writers doing
> > random writes and systematic fdatasync [1]. The failure was caused by
> > three related bugs, because of which BFQ failed to guarantee to
> > high-weight processes the expected fraction of the throughput.
> > 
> 
> Queued on top of Ming's most recent series even though that's still a work
> in progress. I should know in a few days how things stand.

It seems to have cured an interactivity issue I regularly meet during
kbuild final link/depmod phase of fat kernel kbuild, especially bad
with evolution mail usage during that on spinning rust.  Can't really
say for sure given this is not based on measurement.

	-Mike 

  reply	other threads:[~2017-08-31 17:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31  6:46 [PATCH BUGFIX/IMPROVEMENT V2 0/3] three bfq fixes restoring service guarantees with random sync writes in bg Paolo Valente
2017-08-31  6:46 ` [PATCH BUGFIX/IMPROVEMENT V2 1/3] block, bfq: make lookup_next_entity push up vtime on expirations Paolo Valente
2017-08-31  6:46 ` [PATCH BUGFIX/IMPROVEMENT V2 2/3] block, bfq: remove direct switch to an entity in higher class Paolo Valente
2017-08-31  6:46 ` [PATCH BUGFIX/IMPROVEMENT V2 3/3] block, bfq: guarantee update_next_in_service always returns an eligible entity Paolo Valente
2017-08-31 14:21 ` [PATCH BUGFIX/IMPROVEMENT V2 0/3] three bfq fixes restoring service guarantees with random sync writes in bg Jens Axboe
2017-08-31 14:42 ` Mel Gorman
2017-08-31 17:06   ` Mike Galbraith [this message]
2017-08-31 17:12     ` Paolo Valente
2017-08-31 17:31       ` Mike Galbraith
2017-09-04  8:14   ` Mel Gorman
2017-09-04  8:55     ` Paolo Valente
2017-09-04  9:07     ` Ming Lei

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