On Mon, Oct 25, 2021 at 06:20:40AM -0400, Jeff Layton wrote: > On Mon, 2021-10-25 at 11:12 +0100, Luís Henriques wrote: > > On Thu, Oct 21, 2021 at 12:35:18PM -0400, Jeff Layton wrote: > > > On Thu, 2021-10-21 at 12:18 -0400, Patrick Donnelly wrote: > > > > On Thu, Oct 21, 2021 at 11:44 AM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > > > > > > > > On Thu, 2021-10-21 at 09:52 -0400, Patrick Donnelly wrote: > > > > > > On Wed, Oct 20, 2021 at 12:27 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > On Wed, 2021-10-20 at 15:37 +0100, Luís Henriques wrote: > > > > > > > > This counter will keep track of the number of remote object copies done on > > > > > > > > copy_file_range syscalls. This counter will be filesystem per-client, and > > > > > > > > can be accessed from the client debugfs directory. > > > > > > > > > > > > > > > > Cc: Patrick Donnelly <pdonnell@xxxxxxxxxx> > > > > > > > > Signed-off-by: Luís Henriques <lhenriques@xxxxxxx> > > > > > > > > --- > > > > > > > > This is an RFC to reply to Patrick's request in [0]. Note that I'm not > > > > > > > > 100% sure about the usefulness of this patch, or if this is the best way > > > > > > > > to provide the functionality Patrick requested. Anyway, this is just to > > > > > > > > get some feedback, hence the RFC. > > > > > > > > > > > > > > > > Cheers, > > > > > > > > -- > > > > > > > > Luís > > > > > > > > > > > > > > > > [0] https://github.com/ceph/ceph/pull/42720 > > > > > > > > > > > > > > > > > > > > > > I think this would be better integrated into the stats infrastructure. > > > > > > > > > > > > > > Maybe you could add a new set of "copy" stats to struct > > > > > > > ceph_client_metric that tracks the total copy operations done, their > > > > > > > size and latency (similar to read and write ops)? > > > > > > > > > > > > I think it's a good idea to integrate this into "stats" but I think a > > > > > > local debugfs file for some counters is still useful. The "stats" > > > > > > module is immature at this time and I'd rather not build any qa tests > > > > > > (yet) that rely on it. > > > > > > > > > > > > Can we generalize this patch-set to a file named "op_counters" or > > > > > > similar and additionally add other OSD ops performed by the kclient? > > > > > > > > > > > > > > > > > > > > > Tracking this sort of thing is the main purpose of the stats code. I'm > > > > > really not keen on adding a whole separate set of files for reporting > > > > > this. > > > > > > > > Maybe I'm confused. Is there some "file" which is already used for > > > > this type of debugging information? Or do you mean the code for > > > > sending stats to the MDS to support cephfs-top? > > > > > > > > > What's the specific problem with relying on the data in debugfs > > > > > "metrics" file? > > > > > > > > Maybe no problem? I wasn't aware of a "metrics" file. > > > > > > > > > > Yes. For instance: > > > > > > # cat /sys/kernel/debug/ceph/*/metrics > > > item total > > > ------------------------------------------ > > > opened files / total inodes 0 / 4 > > > pinned i_caps / total inodes 5 / 4 > > > opened inodes / total inodes 0 / 4 > > > > > > item total avg_lat(us) min_lat(us) max_lat(us) stdev(us) > > > ----------------------------------------------------------------------------------- > > > read 0 0 0 0 0 > > > write 5 914013 824797 1092343 103476 > > > metadata 79 12856 1572 114572 13262 > > > > > > item total avg_sz(bytes) min_sz(bytes) max_sz(bytes) total_sz(bytes) > > > ---------------------------------------------------------------------------------------- > > > read 0 0 0 0 0 > > > write 5 4194304 4194304 4194304 20971520 > > > > > > item total miss hit > > > ------------------------------------------------- > > > d_lease 11 0 29 > > > caps 5 68 10702 > > > > > > > > > I'm proposing that Luis add new lines for "copy" to go along with the > > > "read" and "write" ones. The "total" counter should give you a count of > > > the number of operations. > > > > The problem with this is that it will require quite some work on the > > MDS-side because, AFAIU, the MDS will need to handle different versions of > > the CEPH_MSG_CLIENT_METRICS message (with and without the new copy-from > > metrics). > > > > Will this extra metric ever be useful on the MDS side? From what I > > understood Patrick's initial request was to have a way to find out, on the > > client, if remote copies are really happening. (*sigh* for not having > > tracepoints.) > > > > Anyway, I can look into adding this to the metrics infrastructure, but > > it'll likely take me some more time to get to it and to figure out (once > > again) how the messages versioning work. > > > > I think it is useful info to report to the MDS, but it's not required to > send these to the MDS to solve the current problem. My suggestion would > be to add what's needed to track these stats in the kclient and report > them via debugfs, but don't send the info to the MDS just yet. > > Later, we could extend the protocol with COPY stats, and add the > necessary infrastructure to the MDS to deal with it. Once that's in > place, we can then extend the kclient to start sending this info along > when it reports the stats. Awesome, that sounds good to me. I'll look into re-writing this patch following your suggestion. Thanks! Cheers, -- Luís
