From: Jens Axboe <axboe@kernel.dk>
To: Dexuan Cui <decui@microsoft.com>,
"'ming.lei@redhat.com'" <ming.lei@redhat.com>,
'Christoph Hellwig' <hch@lst.de>,
"'linux-block@vger.kernel.org'" <linux-block@vger.kernel.org>
Cc: Long Li <longli@microsoft.com>,
"Michael Kelley (LINUX)" <mikelley@microsoft.com>,
"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: Re: Random high CPU utilization in blk-mq with the none scheduler
Date: Sat, 11 Dec 2021 07:21:29 -0700 [thread overview]
Message-ID: <b4350274-7219-1d1f-7a39-3f445c081fd1@kernel.dk> (raw)
In-Reply-To: <BYAPR21MB1270B53CFDDFD52AD942B3AEBF729@BYAPR21MB1270.namprd21.prod.outlook.com>
On 12/11/21 12:09 AM, Dexuan Cui wrote:
>> From: Dexuan Cui
>> Sent: Friday, December 10, 2021 7:45 PM
>>
>>> From: Jens Axboe <axboe@kernel.dk>
>>>
>>> Just out of curiosity, can you do:
>>>
>>> # perf record -a -g -- sleep 3
>>>
>>> when you see the excessive CPU usage, then attach the output of
>>>
>>> # perf report -g
>>>
>>> to a reply?
>
> I realized you only asked for the output of "pref report -g", which
> is much smaller. Please see the attachment for it.
> try_to_grab_pending() is the hottest function, e.g. see line 2479.
Sorry, can you do:
# perf report -g --no-children
instead?
--
Jens Axboe
next prev parent reply other threads:[~2021-12-11 14:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 3:30 Dexuan Cui
2021-12-11 1:29 ` Dexuan Cui
2021-12-11 2:04 ` Jens Axboe
2021-12-11 3:10 ` Dexuan Cui
2021-12-11 3:15 ` Jens Axboe
2021-12-11 3:44 ` Dexuan Cui
2021-12-11 7:09 ` Dexuan Cui
2021-12-11 14:21 ` Jens Axboe [this message]
2021-12-11 18:54 ` Dexuan Cui
2021-12-13 18:43 ` Jens Axboe
2021-12-14 0:43 ` Dexuan Cui
2021-12-13 3:23 ` Ming Lei
2021-12-13 4:20 ` Dexuan Cui
2021-12-13 7:38 ` Ming Lei
2021-12-14 0:31 ` Dexuan Cui
2021-12-14 0:53 ` Ming Lei
2021-12-14 3:09 ` Dexuan Cui
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