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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2019-11-21 13:40:26 +0300
committerJens Axboe <axboe@kernel.dk>2019-11-21 19:06:47 +0300
commitb6866318657717c8914673a6394894d12bc9ff5e (patch)
treef4d534373b711f368f079d0cc54d3d71892e1feb /Documentation/ABI/testing/procfs-diskstats
parent40d47c155e8ae9bcb3f2d0d01cf14d903c664726 (diff)
downloadlinux-b6866318657717c8914673a6394894d12bc9ff5e.tar.xz
block: add iostat counters for flush requests
Requests that triggers flushing volatile writeback cache to disk (barriers) have significant effect to overall performance. Block layer has sophisticated engine for combining several flush requests into one. But there is no statistics for actual flushes executed by disk. Requests which trigger flushes usually are barriers - zero-size writes. This patch adds two iostat counters into /sys/class/block/$dev/stat and /proc/diskstats - count of completed flush requests and their total time. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/ABI/testing/procfs-diskstats')
-rw-r--r--Documentation/ABI/testing/procfs-diskstats5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/procfs-diskstats b/Documentation/ABI/testing/procfs-diskstats
index 2c44b4f1b060..70dcaf2481f4 100644
--- a/Documentation/ABI/testing/procfs-diskstats
+++ b/Documentation/ABI/testing/procfs-diskstats
@@ -29,4 +29,9 @@ Description:
17 - sectors discarded
18 - time spent discarding
+ Kernel 5.5+ appends two more fields for flush requests:
+
+ 19 - flush requests completed successfully
+ 20 - time spent flushing
+
For more details refer to Documentation/admin-guide/iostats.rst