.RE
.TP
.BI fadvise_hint \fR=\fPbool
-Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
+Use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
are likely to be issued. Default: true.
.TP
.BI size \fR=\fPint
more clever block compression attempts, but it will stop naive dedupe
of blocks. Default: true.
.TP
+.BI buffer_compress_percentage \fR=\fPint
+If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
+that compress to the specified level. Fio does this by providing a mix of
+random data and zeroes. Note that this is per block size unit, for file/disk
+wide compression level that matches this setting, you'll also want to set
+\fBrefill_buffers\fR.
+.TP
+.BI buffer_compress_chunk \fR=\fPint
+See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how
+big the ranges of random data and zeroed data is. Without this set, fio will
+provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by
+the remaining zeroed. With this set to some chunk size smaller than the block
+size, fio can alternate random and zeroed data throughout the IO buffer.
+.TP
.BI nrfiles \fR=\fPint
Number of files to use for this job. Default: 1.
.TP
.BI offset \fR=\fPint
Offset in the file to start I/O. Data before the offset will not be touched.
.TP
+.BI offset_increment \fR=\fPint
+If this is provided, then the real offset becomes the
+offset + offset_increment * thread_number, where the thread number is a counter
+that starts at 0 and is incremented for each job. This option is useful if
+there are several jobs which are intended to operate on a file in parallel in
+disjoint segments, with even spacing between the starting points.
+.TP
.BI fsync \fR=\fPint
How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
0, don't sync. Default: 0.
option, the default filename of "jobname_type.log" is used. Even if the
filename is given, fio will still append the type of log.
.TP
+.BI log_avg_msec \fR=\fPint
+By default, fio will log an entry in the iops, latency, or bw log for every
+IO that completes. When writing to the 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.
+.TP
.BI disable_lat \fR=\fPbool
Disable measurements of total latency numbers. Useful only for cutting
back the number of calls to gettimeofday, as that does impact performance at
.BI gid \fR=\fPint
Set group ID, see \fBuid\fR.
.TP
+.BI flow_id \fR=\fPint
+The ID of the flow. If not specified, it defaults to being a global flow. See
+\fBflow\fR.
+.TP
+.BI flow \fR=\fPint
+Weight in token-based flow control. If this value is used, then there is a
+\fBflow counter\fR which is used to regulate the proportion of activity between
+two or more jobs. fio attempts to keep this flow counter near zero. The
+\fBflow\fR parameter stands for how much should be added or subtracted to the
+flow counter on each iteration of the main I/O loop. That is, if one job has
+\fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly
+1:8 ratio in how much one runs vs the other.
+.TP
+.BI flow_watermark \fR=\fPint
+The maximum value that the absolute value of the flow counter is allowed to
+reach before the job must wait for a lower value of the counter.
+.TP
+.BI flow_sleep \fR=\fPint
+The period of time, in microseconds, to wait after the flow watermark has been
+exceeded before retrying operations
+.TP
.BI clat_percentiles \fR=\fPbool
Enable the reporting of percentiles of completion latencies.
.TP
used identically to normal parameters, with the caveat that when used on the
command line, the must come after the ioengine that defines them is selected.
.TP
+.BI (cpu)cpuload \fR=\fPint
+Attempt to use the specified percentage of CPU cycles.
+.TP
+.BI (cpu)cpuchunks \fR=\fPint
+Split the load into cycles of the given time. In microseconds.
+.TP
.BI (libaio)userspace_reap
Normally, with the libaio engine in use, fio will use
the io_getevents system call to reap newly returned events.
projects / fio.git / blobdiff