From: Linhaifeng <haifeng.lin@huawei.com>
To: "linux-perf-users@vger.kernel.org"
<linux-perf-users@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: perf tools:Is there any tools to found out the max latency by irq or cpu idle
Date: Fri, 12 Apr 2019 00:57:24 +0000 [thread overview]
Message-ID: <4099DE2E54AFAD489356C6C9161D53339591D64A@DGGEML502-MBX.china.huawei.com> (raw)
Hi,
I have a single thread application like this:
While (1) {
start = rdtsc();
sqrt (1024);
end = rdtsc();
cycles = end – start;
printf("cycles: %d-%02d-%02d %02d:%02d:%02d: %lu\n",
1900+timeinfo->tm_year, 1+timeinfo->tm_mon, timeinfo->tm_mday, timeinfo->tm_hour, timeinfo->tm_min, timeinfo->tm_sec,
cycles);
}
It print the cycles of sqrt every second and run with taskset –c 1 ./sqrt.
The result of test is:
sqrt 2019-04-10 23:53:50: 43968
sqrt 2019-04-10 23:53:51: 44060
sqrt 2019-04-10 23:53:52: 49012
sqrt 2019-04-10 23:53:53: 38172
sqrt 2019-04-10 23:53:54: 131081408
sqrt 2019-04-10 23:53:55: 43600
sqrt 2019-04-10 23:53:56: 46704
sqrt 2019-04-10 23:53:57: 46880
sqrt 2019-04-10 23:53:58: 44332
……
sqrt 2019-04-10 02:17:15: 131081408
……
sqrt 2019-04-10 04:40:35: 131081408
……
Every 2hour23min there would be a large cycles. I use perf sched not found any sched_switch events.
L2GW_2680:/home/fsp/zn # perf sched record -C 6-11 -o perf.sched
^C[ perf record: Woken up 64 times to write data ]
[ perf record: Captured and wrote 204.878 MB perf.sched (1911189 samples) ]
L2GW_2680:/home/fsp/zn # perf sched latency -i perf.sched
-----------------------------------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Maximum delay at |
-----------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------------
TOTAL: | 0.000 ms | 0 |
---------------------------------------------------
Is there any other tools of perf to found out the max latency by irq or cpu idle ?
next reply other threads:[~2019-04-12 0:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 0:57 Linhaifeng [this message]
2019-04-12 14:06 ` perf tools:Is there any tools to found out the max latency by irq or cpu idle William Cohen
2019-04-13 6:01 ` Linhaifeng
2019-04-14 0:09 ` William Cohen
2019-04-15 12:52 ` Paul Clarke
2019-04-15 17:59 ` Arnaldo Carvalho de Melo
2019-04-16 1:09 ` Linhaifeng
2019-04-16 1:34 ` Linhaifeng
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