Default: 0. A single value applies to reads and writes. Comma-separated
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.
+used. fio must also be run as the root user. Unlike slat/clat/lat stats, which
+can be tracked and reported independently, per priority stats only track and
+report a single type of latency. By default, completion latency (clat) will be
+reported, if \fBlat_percentiles\fR is set, total latency (lat) will be reported.
.TP
.BI (io_uring,libaio)cmdprio_class \fR=\fPint[,int]
Set the I/O priority class to use for I/Os that must be issued with a
\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
projects / fio.git / blobdiff