log: add support for logging max instead of averages

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 4a910a1ac11716d57c3885cf2c2f4fd63f0fa944..6d80360574e0c89899756cbc6a1d9838293c9c81 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1570,8 +1570,12 @@ log_avg_msec=int By default, fio will log an entry in the iops, latency,
                disk log, that can quickly grow to a very large size. Setting
                this option makes fio average the each log entry over the
                specified period of time, reducing the resolution of the log.
-               Defaults to 0.
+               See log_max as well. Defaults to 0, logging all entries.
 
+log_max=bool   If log_avg_msec is set, fio logs the average over that window.
+               If you instead want to log the maximum value, set this option
+               to 1. Defaults to 0, meaning that averaged values are logged.
+.
 log_offset=int If this is set, the iolog options will include the byte
                offset for the IO entry as well as the other data values.