From: junjie.qian@yahoo.com (Junjie Qian)
Subject: Extremely high context switches of i/o to NVM
Date: Fri, 24 Jul 2015 20:00:00 +0000 (UTC) [thread overview]
Message-ID: <2140969145.2200151.1437768000851.JavaMail.yahoo@mail.yahoo.com> (raw)
Hi List,
I run experiment with NVM on NUMA, and found the context switch is extremely high.
The platform is, 1. Linux 4.1-rc7 with multi-queue enabled, kernel is polling enabled (5 secs polling, but the results show little difference between polling and interrupt); 2. 4-socket NUMA machine; 3. Intel PC3700 NVM
The command is sudo perf state -e context-switches nice -n -20 numactl -C 0 fio-master/fio --name=1 --bs=4k --ioengine=libaio --iodepth=1 --rw=read --numjobs=1 --filename=/dev/nvme0n1 --thread --direct=1 --group_reporting --time_based=1 --runtime=60
The result is 3,567,428 context switches.
Would someone give me some help on explaining this? Is this reasonable?
Thanks!
Best
Junjie
next reply other threads:[~2015-07-24 20:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-24 20:00 Junjie Qian [this message]
2015-07-24 20:27 ` Extremely high context switches of i/o to NVM Keith Busch
2015-07-24 23:03 ` Junjie Qian
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