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From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "aherrmann@suse.com" <aherrmann@suse.com>,
	"paolo.valente@linaro.org" <paolo.valente@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Subject: Re: bfq-mq performance comparison to cfq
Date: Mon, 10 Apr 2017 15:15:31 +0000	[thread overview]
Message-ID: <1491837330.4199.1.camel@sandisk.com> (raw)
In-Reply-To: <82BCEB46-8D05-42DA-AE06-3426895A7842@linaro.org>

On Mon, 2017-04-10 at 11:55 +0200, Paolo Valente wrote:
> That said, if you do always want maximum throughput, even at the
> expense of latency, then just switch off low-latency heuristics, i.e.,
> set low_latency to 0.  Depending on the device, setting slice_ilde to
> 0 may help a lot too (as well as with CFQ).  If the throughput is
> still low also after forcing BFQ to an only-throughput mode, then you
> hit some bug, and I'll have a little more work to do ...

Hello Paolo,

Has it been considered to make applications tell the I/O scheduler
whether to optimize for latency or for throughput? It shouldn't be that
hard for window managers and shells to figure out whether or not a new
application that is being started is interactive or not. This would
require a mechanism that allows applications to provide such information
to the I/O scheduler. Wouldn't that be a better approach than the I/O
scheduler trying to guess whether or not an application is an interactive
application?

Bart.=

WARNING: multiple messages have this Message-ID (diff)
From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "aherrmann@suse.com" <aherrmann@suse.com>,
	"paolo.valente@linaro.org" <paolo.valente@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Subject: Re: bfq-mq performance comparison to cfq
Date: Mon, 10 Apr 2017 15:15:31 +0000	[thread overview]
Message-ID: <1491837330.4199.1.camel@sandisk.com> (raw)
In-Reply-To: <82BCEB46-8D05-42DA-AE06-3426895A7842@linaro.org>

On Mon, 2017-04-10 at 11:55 +0200, Paolo Valente wrote:
> That said, if you do always want maximum throughput, even at the
> expense of latency, then just switch off low-latency heuristics, i.e.,
> set low_latency to 0.  Depending on the device, setting slice_ilde to
> 0 may help a lot too (as well as with CFQ).  If the throughput is
> still low also after forcing BFQ to an only-throughput mode, then you
> hit some bug, and I'll have a little more work to do ...

Hello Paolo,

Has it been considered to make applications tell the I/O scheduler
whether to optimize for latency or for throughput? It shouldn't be that
hard for window managers and shells to figure out whether or not a new
application that is being started is interactive or not. This would
require a mechanism that allows applications to provide such information
to the I/O scheduler. Wouldn't that be a better approach than the I/O
scheduler trying to guess whether or not an application is an interactive
application?

Bart.

  reply	other threads:[~2017-04-10 15:15 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-10  9:05 bfq-mq performance comparison to cfq Andreas Herrmann
2017-04-10  9:55 ` Paolo Valente
2017-04-10  9:55   ` Paolo Valente
2017-04-10 15:15   ` Bart Van Assche [this message]
2017-04-10 15:15     ` Bart Van Assche
2017-04-11  7:29     ` Paolo Valente
2017-04-11  7:29       ` Paolo Valente
2017-04-19  5:01       ` Bart Van Assche
2017-04-19  5:01         ` Bart Van Assche
2017-04-19  7:02         ` Paolo Valente
2017-04-19  7:02           ` Paolo Valente
2017-04-19 15:43           ` Bart Van Assche
2017-04-19 15:43             ` Bart Van Assche
2017-04-25  9:40           ` Juri Lelli
2017-04-26  8:18             ` Paolo Valente
2017-04-26  8:18               ` Paolo Valente
2017-04-26 22:12               ` Bart Van Assche
2017-04-26 22:12                 ` Bart Van Assche
2017-04-11  7:26   ` Paolo Valente
2017-04-11  7:26     ` Paolo Valente
2017-04-11 16:31   ` Andreas Herrmann

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