blktrace: add support for scaling and aligning replays

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 3859753ded17edd6bb6c676ccd5915ce6606e334..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 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
@@ -378,6 +382,11 @@ because ZFS doesn't support it. Default: 'posix'.
 Use \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
 are likely to be issued. Default: true.
 .TP
+.BI fadvise_stream \fR=\fPint
+Use \fBposix_fadvise\fR\|(2) to advise the kernel what stream ID the
+writes issued belong to. Only supported on Linux. Note, this option
+may change going forward.
+.TP
 .BI size \fR=\fPint
 Total size of I/O for this job.  \fBfio\fR will run until this many bytes have
 been transferred, unless limited by other options (\fBruntime\fR, for instance,
@@ -650,6 +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.
+.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
@@ -678,6 +694,17 @@ cost of more retrieval system calls.
 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
@@ -1238,6 +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
+.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
@@ -1287,6 +1320,11 @@ a compressed format. They can be decompressed with fio, using the
 \fB\-\-inflate-log\fR command line parameter. The files will be stored with a
 \fB\.fz\fR suffix.
 .TP
+.BI block_error_percentiles \fR=\fPbool
+If set, record errors in trim block-sized units from writes and trims and output
+a histogram of how many trims it took to get to errors, and what kind of error
+was encountered.
+.TP
 .BI disable_lat \fR=\fPbool
 Disable measurements of total latency numbers. Useful only for cutting
 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
@@ -1445,9 +1483,9 @@ exceeded before retrying operations
 Enable the reporting of percentiles of completion latencies.
 .TP
 .BI percentile_list \fR=\fPfloat_list
-Overwrite the default list of percentiles for completion
-latencies. Each number is a floating number in the range (0,100], and
-the maximum length of the list is 20. Use ':' to separate the
+Overwrite the default list of percentiles for completion latencies and the
+block error histogram. Each number is a floating number in the range (0,100],
+and the maximum length of the list is 20. Use ':' to separate the
 numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
 report the values of completion latency below which 99.5% and 99.9% of
 the observed latencies fell, respectively.
@@ -1562,6 +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 (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: