Add total latency log
We log submission and completion latencies, also log total latencies.
This makes it easier to graph and make histograms, if you care only
about the complete latency.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/HOWTO b/HOWTO
index 3af4ce6..7db02b1 100644
--- a/HOWTO
+++ b/HOWTO
@@ -976,15 +976,16 @@
filename. For this option, the postfix is _bw.log.
write_lat_log=str Same as write_bw_log, except that this option stores io
- completion latencies instead. If no filename is given
- with this option, the default filename of "jobname_type.log"
- is used. Even if the filename is given, fio will still
- append the type of log. So if one specifies
+ submission, completion, and total latencies instead. If no
+ filename is given with this option, the default filename of
+ "jobname_type.log" is used. Even if the filename is given,
+ fio will still append the type of log. So if one specifies
write_lat_log=foo
- The actual log names will be foo_clat.log and foo_slat.log.
- This helps fio_generate_plot fine the logs automatically.
+ The actual log names will be foo_slat.log, foo_slat.log,
+ and foo_lat.log. This helps fio_generate_plot fine the logs
+ automatically.
lockmem=int Pin down the specified amount of memory with mlock(2). Can
potentially be used instead of removing memory or booting
@@ -1008,18 +1009,21 @@
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
+disable_lat=bool Disable measurements of total 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_clat=bool Disable measurements of completion latency numbers. See
+ disable_lat.
+
disable_slat=bool Disable measurements of submission latency numbers. See
- disable_clat.
+ disable_slat.
disable_bw=bool Disable measurements of throughput/bandwidth numbers. See
- disable_clat.
+ disable_lat.
gtod_reduce=bool Enable all of the gettimeofday() reducing options
(disable_clat, disable_slat, disable_bw) plus reduce