From: Andreas Herrmann <aherrmann@suse.com>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: bfq-mq performance comparison to cfq
Date: Mon, 10 Apr 2017 11:05:38 +0200 [thread overview]
Message-ID: <20170410090538.GA11473@suselix.suse.de> (raw)
Hi Paolo,
I've looked at your WIP branch as of 4.11.0-bfq-mq-rc4-00155-gbce0818
and did some fio tests to compare the behavior to CFQ.
My understanding is that bfq-mq is supposed to be merged sooner or
later and then it will be the only reasonable I/O scheduler with
blk-mq for rotational devices. Hence I think it is interesting to see
what to expect performance-wise in comparison to CFQ which is usually
used for such devices with the legacy block layer.
I've just done simple tests iterating over number of jobs (1-8 as the
test system had 8 CPUs) for all (random/sequential) read/write
patterns. Fixed set of fio parameters used were '-size=5G
--group_reporting --ioengine=libaio --direct=1 --iodepth=1
--runtime=10'.
I've done 10 runs for each such configuration. The device used was an
older SAMSUNG HD103SJ 1TB disk, SATA attached. Results that stick out
the most are those for sequential reads and sequential writes:
* sequential reads
[0] - cfq, intel_pstate driver, powersave governor
[1] - bfq_mq, intel_pstate driver, powersave governor
jo [0] [1]
bs mean stddev mean stddev
1 & 17060.300 & 77.090 & 17657.500 & 69.602
2 & 15318.200 & 28.817 & 10678.000 & 279.070
3 & 15403.200 & 42.762 & 9874.600 & 93.436
4 & 14521.200 & 624.111 & 9918.700 & 226.425
5 & 13893.900 & 144.354 & 9485.000 & 109.291
6 & 13065.300 & 180.608 & 9419.800 & 75.043
7 & 12169.600 & 95.422 & 9863.800 & 227.662
8 & 12422.200 & 215.535 & 15335.300 & 245.764
* sequential writes
[0] - cfq, intel_pstate driver, powersave governor
[1] - bfq_mq, intel_pstate driver, powersave governor
jo [0] [1]
bs mean stddev mean stddev
1 & 14171.300 & 80.796 & 14392.500 & 182.587
2 & 13520.000 & 88.967 & 9565.400 & 119.400
3 & 13396.100 & 44.936 & 9284.000 & 25.122
4 & 13139.800 & 62.325 & 8846.600 & 45.926
5 & 12942.400 & 45.729 & 8568.700 & 35.852
6 & 12650.600 & 41.283 & 8275.500 & 199.273
7 & 12475.900 & 43.565 & 8252.200 & 33.145
8 & 12307.200 & 43.594 & 13617.500 & 127.773
With performance instead of powersave governor results were
(expectedly) higher but the pattern was the same -- bfq-mq shows a
"dent" for tests with 2-7 fio jobs. At the moment I have no
explanation for this behavior.
Regards,
Andreas
next reply other threads:[~2017-04-10 9:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-10 9:05 Andreas Herrmann [this message]
2017-04-10 9:55 ` bfq-mq performance comparison to cfq Paolo Valente
2017-04-10 9:55 ` Paolo Valente
2017-04-10 15:15 ` Bart Van Assche
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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