blktrace: add support for scaling and aligning replays

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 0f66b3a732f0c66dcf09955defe7ae0a9383ef04..e54e419b2f5852733c7312a44defcf0345be7591 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -286,6 +286,10 @@ Mixed sequential reads and writes.
 .TP
 .B randrw 
 Mixed random reads and writes.
 .TP
 .B randrw 
 Mixed random reads and writes.

+.TP
+.B trimwrite
+Trim and write mixed workload. Blocks will be trimmed first, then the same
+blocks will be written to.

 .RE
 .P
 For mixed I/O, the default split is 50/50. For certain types of io the result
 .RE
 .P
 For mixed I/O, the default split is 50/50. For certain types of io the result


@@ -655,6 +659,13 @@ file out of those files based on the offset generated by fio backend. (see the
 example job file to create such files, use rw=write option). Please note, you
 might want to set necessary environment variables to work with hdfs/libhdfs
 properly.
 example job file to create such files, use rw=write option). Please note, you
 might want to set necessary environment variables to work with hdfs/libhdfs
 properly.

+.TP
+.B mtd
+Read, write and erase an MTD character device (e.g., /dev/mtd0). Discards are
+treated as erases. Depending on the underlying device type, the I/O may have
+to go in a certain pattern, e.g., on NAND, writing sequentially to erase blocks
+and discarding before overwriting. The writetrim mode works well for this
+constraint.

 .RE
 .P
 .RE
 .RE
 .P
 .RE


@@ -683,6 +694,17 @@ cost of more retrieval system calls.
 Low watermark indicating when to start filling the queue again.  Default:
 \fBiodepth\fR. 
 .TP
 Low watermark indicating when to start filling the queue again.  Default:
 \fBiodepth\fR. 
 .TP

+.BI io_submit_mode \fR=\fPstr
+This option controls how fio submits the IO to the IO engine. The default is
+\fBinline\fR, which means that the fio job threads submit and reap IO directly.
+If set to \fBoffload\fR, the job threads will offload IO submission to a
+dedicated pool of IO threads. This requires some coordination and thus has a
+bit of extra overhead, especially for lower queue depth IO where it can
+increase latencies. The benefit is that fio can manage submission rates
+independently of the device completion rates. This avoids skewed latency
+reporting if IO gets back up on the device side (the coordinated omission
+problem).
+.TP

 .BI direct \fR=\fPbool
 If true, use non-buffered I/O (usually O_DIRECT).  Default: false.
 .TP
 .BI direct \fR=\fPbool
 If true, use non-buffered I/O (usually O_DIRECT).  Default: false.
 .TP


@@ -1243,6 +1265,12 @@ is to replay the IOPS onto the major/minor device that each IOP was recorded
 from.  Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
 single specified device regardless of the device it was recorded from.
 .TP
 from.  Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
 single specified device regardless of the device it was recorded from.
 .TP

+.BI replay_align \fR=\fPint
+Force alignment of IO offsets and lengths in a trace to this power of 2 value.
+.TP
+.BI replay_scale \fR=\fPint
+Scale sector offsets down by this factor when replaying traces.
+.TP

 .BI write_bw_log \fR=\fPstr
 If given, write a bandwidth log of the jobs in this job file. Can be used to
 store data of the bandwidth of the jobs in their lifetime. The included
 .BI write_bw_log \fR=\fPstr
 If given, write a bandwidth log of the jobs in this job file. Can be used to
 store data of the bandwidth of the jobs in their lifetime. The included


@@ -1572,6 +1600,9 @@ Specifies the name of the Ceph pool containing the RBD.
 .TP
 .BI (rbd)clientname \fR=\fPstr
 Specifies the username (without the 'client.' prefix) used to access the Ceph cluster.
 .TP
 .BI (rbd)clientname \fR=\fPstr
 Specifies the username (without the 'client.' prefix) used to access the Ceph cluster.

+.TP
+.BI (mtd)skipbad \fR=\fPbool
+Skip operations against known bad blocks.

 .SH OUTPUT
 While running, \fBfio\fR will display the status of the created jobs.  For
 example:
 .SH OUTPUT
 While running, \fBfio\fR will display the status of the created jobs.  For
 example: