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

From: Jeff Layton <jlayton@redhat.com>
To: Venky Shankar <vshankar@redhat.com>, idryomov@gmail.com
Cc: xiubli@redhat.com, ceph-devel@vger.kernel.org
Subject: Re: [PATCH v2 0/4] ceph: forward average read/write/metadata latency
Date: Tue, 08 Mar 2022 10:58:22 -0500	[thread overview]
Message-ID: <4e82e2ac560baad2ab51d0b92ffb6fdfcadf48aa.camel@redhat.com> (raw)
In-Reply-To: <20220308124219.771527-1-vshankar@redhat.com>

On Tue, 2022-03-08 at 07:42 -0500, 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(-)
> 

Thanks Venky. New version is now merged into testing.
-- 
Jeff Layton <jlayton@redhat.com>