Re: [PATCH v2 0/4] ceph: forward average read/write/metadata latency

[Xiubo Li <xiubli@redhat.com>]

On 3/8/22 8:42 PM, Venky Shankar wrote:
> v2
>    - rename to_ceph_timespec() to ktime_to_ceph_timespec()
>    - use ceph_encode_timespec64() helper
>
> Jeff,
>
> To apply these, please drop commit range f4bf256..840d9f0 from testing branch.
>
> Right now, cumulative read/write/metadata latencies are tracked
> and are periodically forwarded to the MDS. These meterics are not
> particularly useful. A much more useful metric is the average latency
> and standard deviation (stdev) which is what this series of patches
> aims to do.
>
> The userspace (libcephfs+tool) changes are here::
>
>            https://github.com/ceph/ceph/pull/41397
>
> Note that the cumulative latencies are still forwarded to the MDS but
> the tool (cephfs-top) ignores it altogether.
>
> Latency standard deviation is calculated in `cephfs-top` tool.
>
> Venky Shankar (4):
>    ceph: use ktime_to_timespec64() rather than jiffies_to_timespec64()
>    ceph: track average r/w/m latency
>    ceph: include average/stdev r/w/m latency in mds metrics
>    ceph: use tracked average r/w/m latencies to display metrics in
>      debugfs
>
>   fs/ceph/debugfs.c |  5 ++--
>   fs/ceph/metric.c  | 63 +++++++++++++++++++++++++++--------------------
>   fs/ceph/metric.h  | 63 ++++++++++++++++++++++++++++++-----------------
>   3 files changed, 79 insertions(+), 52 deletions(-)
>
The series LGTM.

Reviewed-by: Xiubo Li <xiubli@redhat.com>