[lustre-discuss] 2.10.0 CentOS6.9 ksoftirqd CPU load

[Hans Henrik Happe]

Just for the record. 2.11.0 has fixed this. Not sure which LU though.

Cheers,
Hans Henrik

On 30-09-2017 23:43, Hans Henrik Happe wrote:
> On 27-09-2017 18:50, Dilger, Andreas wrote:
>> On Sep 26, 2017, at 01:10, Hans Henrik Happe<happe at nbi.dk>  wrote:
>>> Hi,
>>>
>>> Did anyone else experience CPU load from ksoftirqd after 'modprobe
>>> lustre'? On an otherwise idle node I see:
>>>
>>>   PID USER      PR   NI VIRT  RES  SHR S %CPU  %MEM TIME+   COMMAND
>>>     9 root      20   0     0    0    0 S 28.5  0.0  2:05.58 ksoftirqd/1
>>>
>>>
>>>    57 root      20   0     0    0    0 R 23.9  0.0  2:22.91 ksoftirqd/13
>>>
>>> The sum of those two is about 50% CPU.
>>>
>>> I have narrowed it down to the ptlrpc module. When I remove that, it stops.
>>>
>>> I also tested the 2.10.1-RC1, which is the same.
>> If you can run "echo l > /proc/sysrq-trigger" it will report the processes
>> that are currently running on the CPUs of your system to the console (and
>> also /var/log/messages, if it can write everything in time).
>>
>> You might need to do this several times to get a representative sample of
>> the ksoftirqd process stacks to see what they are doing that is consuming
>> so much CPU.
>>
>> Alternately, "echo t > /proc/sysrq-trigger" will report the stacks of all
>> processes to the console (and /v/l/m), but there will be a lot of them,
>> and no better chance that it catches what ksoftirqd is doing 25% of the time.
> I've attached the stacks. Some wakeup which I guess are initiated by 
> something in the ptlrpc code.
> 
> Cheers,
> Hans Henrik
> 
> 
> 
> 
> _______________________________________________
> lustre-discuss mailing list
> lustre-discuss at lists.lustre.org
> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
>