From bdca3c87fb7ad1cc61d231d37eb0d8f90d001e0c Mon Sep 17 00:00:00 2001 From: Michael Callahan Date: Wed, 18 Jul 2018 04:47:40 -0700 Subject: block: Track DISCARD statistics and output them in stat and diskstat Add tracking of REQ_OP_DISCARD ios to the partition statistics and append them to the various stat files in /sys as well as /proc/diskstats. These are tracked with the same four stats as reads and writes: Number of discard ios completed. Number of discard ios merged Number of discard sectors completed Milliseconds spent on discard requests This is done via adding a new STAT_DISCARD define to genhd.h and then using it to index that stat field for discard requests. tj: Refreshed on top of v4.17 and other previous updates. Signed-off-by: Michael Callahan Signed-off-by: Tejun Heo Cc: Andy Newell Signed-off-by: Jens Axboe --- Documentation/iostats.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'Documentation/iostats.txt') diff --git a/Documentation/iostats.txt b/Documentation/iostats.txt index 04d394a2e06c..49df45f90e8a 100644 --- a/Documentation/iostats.txt +++ b/Documentation/iostats.txt @@ -31,6 +31,9 @@ Here are examples of these different formats:: 3 0 hda 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 3376340 23705160 3 1 hda1 35486 38030 38030 38030 + 4.18+ diskstats: + 3 0 hda 446216 784926 9550688 4382310 424847 312726 5922052 19310380 0 3376340 23705160 0 0 0 0 + On 2.4 you might execute ``grep 'hda ' /proc/partitions``. On 2.6+, you have a choice of ``cat /sys/block/hda/stat`` or ``grep 'hda ' /proc/diskstats``. @@ -101,6 +104,18 @@ Field 11 -- weighted # of milliseconds spent doing I/Os last update of this field. This can provide an easy measure of both I/O completion time and the backlog that may be accumulating. +Field 12 -- # of discards completed + This is the total number of discards completed successfully. + +Field 13 -- # of discards merged + See the description of field 2 + +Field 14 -- # of sectors discarded + This is the total number of sectors discarded successfully. + +Field 15 -- # of milliseconds spent discarding + This is the total number of milliseconds spent by all discards (as + measured from __make_request() to end_that_request_last()). To avoid introducing performance bottlenecks, no locks are held while modifying these counters. This implies that minor inaccuracies may be -- cgit v1.2.3-58-ga151