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

[Hans Henrik Happe]

Happy to report that 2.10.4 fixed this issue.

Cheers,
Hans Henrik

On 06-04-2018 14:48, Hans Henrik Happe wrote:
> 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
>>
>>
>>
>>
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