fio: Introduce the log_entries option

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 78988c9e829ee7ecd37e44cbe043250cbfcdd02d..a6469541d22fb5ec8a9a4fb93c41e3d73c1cb468 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -1965,8 +1965,7 @@ with the caveat that when used on the command line, they must come after the
 .BI (io_uring,libaio)cmdprio_percentage \fR=\fPint[,int]
 Set the percentage of I/O that will be issued with the highest priority.
 Default: 0. A single value applies to reads and writes. Comma-separated
-values may be specified for reads and writes. This option cannot be used
-with the `prio` or `prioclass` options. For this option to be effective,
+values may be specified for reads and writes. For this option to be effective,
 NCQ priority must be supported and enabled, and `direct=1' option must be
 used. fio must also be run as the root user.
 .TP
@@ -3244,6 +3243,17 @@ logging (see \fBlog_avg_msec\fR) has been enabled. See
 \fBwrite_bw_log\fR for details about the filename format and \fBLOG
 FILE FORMATS\fR for how data is structured within the file.
 .TP
+.BI log_entries \fR=\fPint
+By default, fio will log an entry in the iops, latency, or bw log for
+every I/O that completes. The initial number of I/O log entries is 1024.
+When the log entries are all used, new log entries are dynamically
+allocated.  This dynamic log entry allocation may negatively impact
+time-related statistics such as I/O tail latencies (e.g. 99.9th percentile
+completion latency). This option allows specifying a larger initial
+number of log entries to avoid run-time allocation of new log entries,
+resulting in more precise time-related I/O statistics.
+Also see \fBlog_avg_msec\fR as well. Defaults to 1024.
+.TP
 .BI log_avg_msec \fR=\fPint
 By default, fio will log an entry in the iops, latency, or bw log for every
 I/O that completes. When writing to the disk log, that can quickly grow to a