.B e4defrag
IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity
request to DDIR_WRITE event
-.TP
.RE
+.P
.RE
.TP
.BI iodepth \fR=\fPint
asked to limit reads or writes to a certain rate. If that is the case, then
the distribution may be skewed. Default: 50.
.TP
+.BI random_distribution \fR=\fPstr:float
+By default, fio will use a completely uniform random distribution when asked
+to perform random IO. Sometimes it is useful to skew the distribution in
+specific ways, ensuring that some parts of the data is more hot than others.
+Fio includes the following distribution models:
+.RS
+.TP
+.B random
+Uniform random distribution
+.TP
+.B zipf
+Zipf distribution
+.TP
+.B pareto
+Pareto distribution
+.TP
+.RE
+.P
+When using a zipf or pareto distribution, an input value is also needed to
+define the access pattern. For zipf, this is the zipf theta. For pareto,
+it's the pareto power. Fio includes a test program, genzipf, that can be
+used visualize what the given input values will yield in terms of hit rates.
+If you wanted to use zipf with a theta of 1.2, you would use
+random_distribution=zipf:1.2 as the option. If a non-uniform model is used,
+fio will disable use of the random map.
+.TP
.B norandommap
Normally \fBfio\fR will cover every block of the file when doing random I/O. If
this parameter is given, a new offset will be chosen without looking at past
random block map. As coverage will not be as complete as with random maps, this
option is disabled by default.
.TP
+.BI random_generator \fR=\fPstr
+Fio supports the following engines for generating IO offsets for random IO:
+.RS
+.TP
+.B tausworthe
+Strong 2^88 cycle random number generator
+.TP
+.B lfsr
+Linear feedback shift register generator
+.TP
+.RE
+.P
+Tausworthe is a strong random number generator, but it requires tracking on the
+side if we want to ensure that blocks are only read or written once. LFSR
+guarantees that we never generate the same offset twice, and it's also less
+computationally expensive. It's not a true random generator, however, though
+for IO purposes it's typically good enough. LFSR only works with single block
+sizes, not with workloads that use multiple block sizes. If used with such a
+workload, fio may read or write some blocks multiple times.
+.TP
.BI nice \fR=\fPint
Run job with given nice value. See \fInice\fR\|(2).
.TP
Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
milliseconds. Default: 1000ms.
.TP
+.BI max_latency \fR=\fPint
+If set, fio will exit the job if it exceeds this maximum latency. It will exit
+with an ETIME error.
+.TP
.BI cpumask \fR=\fPint
Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
may run on. See \fBsched_setaffinity\fR\|(2).
.BI cpus_allowed \fR=\fPstr
Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
.TP
+.BI numa_cpu_nodes \fR=\fPstr
+Set this job running on spcified NUMA nodes' CPUs. The arguments allow
+comma delimited list of cpu numbers, A-B ranges, or 'all'.
+.TP
+.BI numa_mem_policy \fR=\fPstr
+Set this job's memory policy and corresponding NUMA nodes. Format of
+the argements:
+.RS
+.TP
+.B <mode>[:<nodelist>]
+.TP
+.B mode
+is one of the following memory policy:
+.TP
+.B default, prefer, bind, interleave, local
+.TP
+.RE
+For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is
+needed to be specified. For \fBprefer\fR, only one node is
+allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows
+comma delimited list of numbers, A-B ranges, or 'all'.
+.TP
.BI startdelay \fR=\fPint
Delay start of job for the specified number of seconds.
.TP
connections rather than initiating an outgoing connection. The
hostname must be omitted if this option is used.
.TP
+.BI (net, pingpong) \fR=\fPbool
+Normal a network writer will just continue writing data, and a network reader
+will just consume packages. If pingpong=1 is set, a writer will send its normal
+payload to the reader, then wait for the reader to send the same payload back.
+This allows fio to measure network latencies. The submission and completion
+latencies then measure local time spent sending or receiving, and the
+completion latency measures how long it took for the other end to receive and
+send back.
+.TP
.BI (e4defrag,donorname) \fR=\fPstr
File will be used as a block donor (swap extents between files)
.TP