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authorMichael Callahan <michaelcallahan@fb.com>2018-07-18 04:47:40 -0700
committerJens Axboe <axboe@kernel.dk>2018-07-18 08:44:22 -0600
commitbdca3c87fb7ad1cc61d231d37eb0d8f90d001e0c (patch)
treea5890cef3e0fb586f2a2b2a366423e71af96d821 /Documentation/block
parentddcf35d397976421a4ec1d0d00fbcc027a8cb034 (diff)
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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 <michaelcallahan@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andy Newell <newella@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/block')
-rw-r--r--Documentation/block/stat.txt28
1 files changed, 16 insertions, 12 deletions
diff --git a/Documentation/block/stat.txt b/Documentation/block/stat.txt
index 0dbc946de2ea..0aace9cc536c 100644
--- a/Documentation/block/stat.txt
+++ b/Documentation/block/stat.txt
@@ -31,28 +31,32 @@ write ticks milliseconds total wait time for write requests
in_flight requests number of I/Os currently in flight
io_ticks milliseconds total time this block device has been active
time_in_queue milliseconds total wait time for all requests
+discard I/Os requests number of discard I/Os processed
+discard merges requests number of discard I/Os merged with in-queue I/O
+discard sectors sectors number of sectors discarded
+discard ticks milliseconds total wait time for discard requests
-read I/Os, write I/Os
-=====================
+read I/Os, write I/Os, discard I/0s
+===================================
These values increment when an I/O request completes.
-read merges, write merges
-=========================
+read merges, write merges, discard merges
+=========================================
These values increment when an I/O request is merged with an
already-queued I/O request.
-read sectors, write sectors
-===========================
+read sectors, write sectors, discard_sectors
+============================================
-These values count the number of sectors read from or written to this
-block device. The "sectors" in question are the standard UNIX 512-byte
-sectors, not any device- or filesystem-specific block size. The
-counters are incremented when the I/O completes.
+These values count the number of sectors read from, written to, or
+discarded from this block device. The "sectors" in question are the
+standard UNIX 512-byte sectors, not any device- or filesystem-specific
+block size. The counters are incremented when the I/O completes.
-read ticks, write ticks
-=======================
+read ticks, write ticks, discard ticks
+======================================
These values count the number of milliseconds that I/O requests have
waited on this block device. If there are multiple I/O requests waiting,