Re: Random high CPU utilization in blk-mq with the none scheduler

Jens Axboe
2021-12-11T14:21:36Z

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