From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo 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 Message-ID: <20190415175907.GC11294@kernel.org> References: <4099DE2E54AFAD489356C6C9161D53339591D64A@DGGEML502-MBX.china.huawei.com> <8ce8c596-123e-1342-5ccc-06a5fd8a60ec@redhat.com> <4099DE2E54AFAD489356C6C9161D53339591DE6D@DGGEML502-MBX.china.huawei.com> <6e6a98a4-a442-1e10-cf5a-56b6792d42ba@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <6e6a98a4-a442-1e10-cf5a-56b6792d42ba@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: Paul Clarke Cc: Linhaifeng , "linux-perf-users@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-Id: linux-perf-users.vger.kernel.org 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