diff options
| author | Jan Kara <jack@suse.cz> | 2020-06-17 15:58:23 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-06-26 05:06:11 +0200 |
| commit | f3bdc62fd82ed93dbe4d049eacba310de7eb2a6a (patch) | |
| tree | eefbacc996ba10e58a127a7a2df8924e4bbb0179 /include/trace | |
| parent | block: move struct block_device to blk_types.h (diff) | |
| download | linux-f3bdc62fd82ed93dbe4d049eacba310de7eb2a6a.tar.xz linux-f3bdc62fd82ed93dbe4d049eacba310de7eb2a6a.zip | |
blktrace: Provide event for request merging
Currently blk-mq does not report any event when two requests get merged
in the elevator. This then results in difficult to understand sequence
of events like:
...
8,0 34 1579 0.608765271 2718 I WS 215023504 + 40 [dbench]
8,0 34 1584 0.609184613 2719 A WS 215023544 + 56 <- (8,4) 2160568
8,0 34 1585 0.609184850 2719 Q WS 215023544 + 56 [dbench]
8,0 34 1586 0.609188524 2719 G WS 215023544 + 56 [dbench]
8,0 3 602 0.609684162 773 D WS 215023504 + 96 [kworker/3:1H]
8,0 34 1591 0.609843593 0 C WS 215023504 + 96 [0]
and you can only guess (after quite some headscratching since the above
excerpt is intermixed with a lot of other IO) that request 215023544+56
got merged to request 215023504+40. Provide proper event for request
merging like we used to do in the legacy block layer.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/trace')
| -rw-r--r-- | include/trace/events/block.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 93b114226af8..34d64ca306b1 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -212,6 +212,21 @@ DEFINE_EVENT(block_rq, block_rq_issue, ); /** + * block_rq_merge - merge request with another one in the elevator + * @q: queue holding operation + * @rq: block IO operation operation request + * + * Called when block operation request @rq from queue @q is merged to another + * request queued in the elevator. + */ +DEFINE_EVENT(block_rq, block_rq_merge, + + TP_PROTO(struct request_queue *q, struct request *rq), + + TP_ARGS(q, rq) +); + +/** * block_bio_bounce - used bounce buffer when processing block operation * @q: queue holding the block operation * @bio: block operation |