From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Paul Clarke <pc@us.ibm.com>
Cc: Linhaifeng <haifeng.lin@huawei.com>,
"linux-perf-users@vger.kernel.org"
<linux-perf-users@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: perf tools:Is there any tools to found out the max latency by irq or cpu idle
Date: Mon, 15 Apr 2019 14:59:07 -0300 [thread overview]
Message-ID: <20190415175907.GC11294@kernel.org> (raw)
In-Reply-To: <6e6a98a4-a442-1e10-cf5a-56b6792d42ba@us.ibm.com>
Em Mon, Apr 15, 2019 at 07:52:59AM -0500, Paul Clarke escreveu:
> On 4/13/19 1:01 AM, Linhaifeng wrote:
> > Sorry, the value 131081408 is just for example. Actually the result is like this:
> > 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: 136345876
> > ……
> > sqrt 2019-04-10 04:40:35: 136335644
> > ……
>
> Given the periodicity, I'm wondering if it could be System Management Interrupts (SMIs)?
>
> If so, some BIOSes have settings to mitigate, otherwise, there's not much that can be done, per my understanding.
[root@quaco perf]# perf list smi
List of pre-defined events (to be used in -e):
msr/smi/ [Kernel PMU event]
sunrpc:xprt_transmit [Tracepoint event]
tcp:tcp_retransmit_skb [Tracepoint event]
tcp:tcp_retransmit_synack [Tracepoint event]
sdt_qemu:qmp_block_job_dismiss [SDT event]
sdt_qemu:qmp_job_dismiss [SDT event]
Metric Groups:
[root@quaco perf]#
Here, using it:
[root@quaco perf]# perf stat -I 1000 -e msr/smi/
# time counts unit events
1.000919819 0 msr/smi/
2.001689950 0 msr/smi/
3.002266988 0 msr/smi/
4.003049439 16 msr/smi/
5.003676064 0 msr/smi/
6.004420613 16 msr/smi/
^C 6.609405666 0 msr/smi/
[root@quaco perf]#
In this Lenovo T480s I generate SMIs by pressing the mute button :-)
- Arnaldo
next prev parent reply other threads:[~2019-04-15 17:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-12 0:57 perf tools:Is there any tools to found out the max latency by irq or cpu idle Linhaifeng
2019-04-12 14:06 ` 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 [this message]
2019-04-16 1:09 ` Linhaifeng
2019-04-16 1:34 ` Linhaifeng
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