Add options for disabling slat/clat/bw measurements
Useful for cutting down on the number of gettimeofday calls in
situations where that does impact performance. This is mostly for
really high IOPS rates.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index 129926b..1d1aa61 100644
--- a/HOWTO
+++ b/HOWTO
@@ -835,6 +835,19 @@
disk_util=bool Generate disk utilization statistics, if the platform
supports it. Defaults to on.
+disable_clat=bool Disable measurements of completion latency numbers. Useful
+ only for cutting back the number of calls to gettimeofday,
+ as that does impact performance at really high IOPS rates.
+ Note that to really get rid of a large amount of these
+ calls, this option must be used with disable_slat and
+ disable_bw as well.
+
+disable_slat=bool Disable measurements of submission latency numbers. See
+ disable_clat.
+
+disable_bw=bool Disable measurements of throughput/bandwidth numbers. See
+ disable_clat.
+
6.0 Interpreting the output
---------------------------