Re: [PATCH v9 0/5] ceph: add perf metrics support

[Xiubo Li <xiubli@redhat.com>]

On 2020/3/9 20:09, Jeff Layton wrote:
> On Mon, 2020-03-09 at 03:37 -0400, xiubli@redhat.com wrote:
>> From: Xiubo Li <xiubli@redhat.com>
>>
>> Changed in V9:
>> - add an r_ended field to the mds request struct and use that to calculate the metric
>> - fix some commit comments
>>
>> We can get the metrics from the debugfs:
>>
>> $ cat /sys/kernel/debug/ceph/0c93a60d-5645-4c46-8568-4c8f63db4c7f.client4267/metrics
>> item          total       sum_lat(us)     avg_lat(us)
>> -----------------------------------------------------
>> read          13          417000          32076
>> write         42          131205000       3123928
>> metadata      104         493000          4740
>>
>> item          total           miss            hit
>> -------------------------------------------------
>> d_lease       204             0               918
>> caps          204             213             368218
>>
> Thanks Xiubo! This looks good. One minor issue with the cap patch, but I
> can just fix that up before merging if you're ok with my proposed
> change.
>
> Beyond this...while average latency is a good metric, it's often not
> enough to help diagnose problems. I wonder if we ought to be at least
> tracking min/max latency for all calls too. I wonder if there's way to
> track standard deviation too? That would be really nice to have.

yeah, the min/max latencies here make sense, it is on my todo list and I 
will do it after this patch series.

And for the standard deviation I will try to have a investigate of it.

Thanks

> Cheers,