From: Jens Axboe <axboe@kernel.dk>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ulf.hansson@linaro.org, broonie@kernel.org,
mgorman@techsingularity.net, 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 08:21:00 -0600 [thread overview]
Message-ID: <da37f9a6-4954-3e70-f807-3b3daa7d9dd3@kernel.dk> (raw)
In-Reply-To: <20170831064631.2223-1-paolo.valente@linaro.org>
On 08/31/2017 12:46 AM, 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.
>
> The three patches in this series fix these bugs. These fixes restore
> the usual BFQ service guarantees (and thus optimal responsiveness
> too), against the above background workload and, probably, against
> other similar workloads.
Applied for 4.14, thanks Paolo.
--
Jens Axboe
next prev parent reply other threads:[~2017-08-31 14:21 UTC|newest]
Thread overview: 16+ 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 ` Jens Axboe [this message]
2017-08-31 14:42 ` [PATCH BUGFIX/IMPROVEMENT V2 0/3] three bfq fixes restoring service guarantees with random sync writes in bg Mel Gorman
2017-08-31 17:06 ` Mike Galbraith
2017-08-31 17:06 ` Mike Galbraith
2017-08-31 17:12 ` Paolo Valente
2017-08-31 17:12 ` Paolo Valente
2017-08-31 17:31 ` Mike Galbraith
2017-08-31 17:31 ` Mike Galbraith
2017-09-04 8:14 ` Mel Gorman
2017-09-04 8:55 ` Paolo Valente
2017-09-04 8:55 ` Paolo Valente
2017-09-04 9:07 ` Ming Lei
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