From: Paolo Valente <paolo.valente@linaro.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Ming Lei <tom.leiming@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-block <linux-block@vger.kernel.org>
Subject: Re: Switching to MQ by default may generate some bug reports
Date: Thu, 3 Aug 2017 11:44:06 +0200 [thread overview]
Message-ID: <DAC70C00-B51D-4752-8EA7-EA55368918EC@linaro.org> (raw)
In-Reply-To: <20170803094242.wol67mmga3om4gjp@techsingularity.net>
> Il giorno 03 ago 2017, alle ore 11:42, Mel Gorman <mgorman@techsingularity.net> ha scritto:
>
> On Thu, Aug 03, 2017 at 05:17:21PM +0800, Ming Lei wrote:
>> Hi Mel Gorman,
>>
>> On Thu, Aug 3, 2017 at 4:51 PM, Mel Gorman <mgorman@techsingularity.net> wrote:
>>> Hi Christoph,
>>>
>>> I know the reasons for switching to MQ by default but just be aware that it's
>>> not without hazards albeit it the biggest issues I've seen are switching
>>> CFQ to BFQ. On my home grid, there is some experimental automatic testing
>>> running every few weeks searching for regressions. Yesterday, it noticed
>>> that creating some work files for a postgres simulator called pgioperf
>>> was 38.33% slower and it auto-bisected to the switch to MQ. This is just
>>> linearly writing two files for testing on another benchmark and is not
>>> remarkable. The relevant part of the report is
>>
>> We saw some SCSI-MQ performance issue too, please see if the following
>> patchset fixes your issue:
>>
>> http://marc.info/?l=linux-block&m=150151989915776&w=2
>>
>
> That series is dealing with problems with legacy-deadline vs mq-none where
> as the bulk of the problems reported in this mail are related to
> legacy-CFQ vs mq-BFQ.
>
Out-of-curiosity: you get no regression with mq-none or mq-deadline?
Thanks,
Paolo
> --
> Mel Gorman
> SUSE Labs
next prev parent reply other threads:[~2017-08-03 9:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-03 8:51 Switching to MQ by default may generate some bug reports Mel Gorman
2017-08-03 9:17 ` Ming Lei
2017-08-03 9:32 ` Ming Lei
2017-08-03 9:42 ` Mel Gorman
2017-08-03 9:44 ` Paolo Valente [this message]
2017-08-03 10:46 ` Mel Gorman
2017-08-03 9:57 ` Ming Lei
2017-08-03 10:47 ` Mel Gorman
2017-08-03 11:48 ` Ming Lei
2017-08-03 9:21 ` Paolo Valente
2017-08-03 11:01 ` Mel Gorman
2017-08-04 7:26 ` Paolo Valente
2017-08-04 11:01 ` Mel Gorman
2017-08-04 22:05 ` Paolo Valente
2017-08-05 11:54 ` Mel Gorman
2017-08-07 17:35 ` Paolo Valente
2017-08-07 17:32 ` Paolo Valente
2017-08-07 18:42 ` Paolo Valente
2017-08-08 8:06 ` Paolo Valente
2017-08-08 17:33 ` Paolo Valente
2017-08-08 18:27 ` Mel Gorman
2017-08-09 21:49 ` Paolo Valente
2017-08-10 8:44 ` Mel Gorman
2017-08-08 10:30 ` Mel Gorman
2017-08-08 10:43 ` Ming Lei
2017-08-08 11:27 ` Mel Gorman
2017-08-08 11:49 ` Ming Lei
2017-08-08 11:55 ` Mel Gorman
2017-08-08 17:16 ` Paolo Valente
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