Enable request flow under Poisson process

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 140c9bb5356be7f5fc51dfbb040fd01207ef354e..2ecc3d3300f389dc37ab0193005d3e5f899abf3f 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -288,7 +288,7 @@ Random trim (Linux block devices only).
 .B rw, readwrite
 Mixed sequential reads and writes.
 .TP
-.B randrw 
+.B randrw
 Mixed random reads and writes.
 .TP
 .B trimwrite
@@ -658,8 +658,8 @@ IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment acti
 request to DDIR_WRITE event
 .TP
 .B rbd
-IO engine supporting direct access to Ceph Rados Block Devices (RBD) via librbd 
-without the need to use the kernel rbd driver. This ioengine defines engine specific 
+IO engine supporting direct access to Ceph Rados Block Devices (RBD) via librbd
+without the need to use the kernel rbd driver. This ioengine defines engine specific
 options.
 .TP
 .B gfapi
@@ -750,7 +750,7 @@ we simply do polling.
 .TP
 .BI iodepth_low \fR=\fPint
 Low watermark indicating when to start filling the queue again.  Default:
-\fBiodepth\fR. 
+\fBiodepth\fR.
 .TP
 .BI io_submit_mode \fR=\fPstr
 This option controls how fio submits the IO to the IO engine. The default is
@@ -963,6 +963,10 @@ size is used as the metric.
 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
 is used for read vs write separation.
 .TP
+.BI poisson \fR=\fPbool
+When rate limited, try simulate request flow under Poisson process (instead
+of even distribution). Default: false.
+.TP
 .BI ratecycle \fR=\fPint
 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
 milliseconds.  Default: 1000ms.
@@ -1280,8 +1284,8 @@ only N blocks before verifying these blocks.
 .BI verify_backlog_batch \fR=\fPint
 Control how many blocks fio will verify if verify_backlog is set. If not set,
 will default to the value of \fBverify_backlog\fR (meaning the entire queue is
-read back and verified).  If \fBverify_backlog_batch\fR is less than 
-\fBverify_backlog\fR then not all blocks will be verified,  if 
+read back and verified).  If \fBverify_backlog_batch\fR is less than
+\fBverify_backlog\fR then not all blocks will be verified,  if
 \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR,  some blocks
 will be verified more than once.
 .TP
@@ -1320,7 +1324,7 @@ Start a new reporting group.  If not given, all jobs in a file will be part
 of the same reporting group, unless separated by a stonewall.
 .TP
 .BI numjobs \fR=\fPint
-Number of clones (processes/threads performing the same workload) of this job.  
+Number of clones (processes/threads performing the same workload) of this job.
 Default: 1.
 .TP
 .B group_reporting
@@ -1513,8 +1517,8 @@ errors for given error type is separated with ':'.
 Error may be symbol ('ENOSPC', 'ENOMEM') or an integer.
 .br
 Example: ignore_error=EAGAIN,ENOSPC:122 .
-.br    
-This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE. 
+.br
+This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE.
 .TP
 .BI error_dump \fR=\fPbool
 If set dump every error even if it is non fatal, true by default. If disabled
@@ -1687,7 +1691,7 @@ Set the TCP maximum segment size (TCP_MAXSEG).
 File will be used as a block donor (swap extents between files)
 .TP
 .BI (e4defrag,inplace) \fR=\fPint
-Configure donor file block allocation strategy         
+Configure donor file block allocation strategy
 .RS
 .BI 0(default) :
 Preallocate donor's file on init
@@ -1951,7 +1955,7 @@ Disk utilization (1 for each disk used):
 .P
 Error Info (dependent on continue_on_error, default off):
 .RS
-.B total # errors, first error code 
+.B total # errors, first error code
 .RE
 .P
 .B text description (if provided in config - appears on newline)
@@ -2018,7 +2022,7 @@ fio \-\-client=server \-\-remote-config /path/to/file.fio
 Then fio will open this local (to the server) job file instead
 of being passed one from the client.
 
-If you have many servers (example: 100 VMs/containers), you can input a pathname 
+If you have many servers (example: 100 VMs/containers), you can input a pathname
 of a file containing host IPs/names as the parameter value for the \-\-client option.
 For example, here is an example "host.list" file containing 2 hostnames:
 
@@ -2034,8 +2038,8 @@ In this mode, you cannot input server-specific parameters or job files, and all
 servers receive the same job file.
 
 In order to enable fio \-\-client runs utilizing a shared filesystem from multiple hosts,
-fio \-\-client now prepends the IP address of the server to the filename. For example, 
-if fio is using directory /mnt/nfs/fio and is writing filename fileio.tmp, 
+fio \-\-client now prepends the IP address of the server to the filename. For example,
+if fio is using directory /mnt/nfs/fio and is writing filename fileio.tmp,
 with a \-\-client hostfile
 containing two hostnames h1 and h2 with IP addresses 192.168.10.120 and 192.168.10.121, then
 fio will create two files:
@@ -2059,4 +2063,3 @@ See \fBREADME\fR.
 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
 .br
 Sample jobfiles are available in the \fBexamples\fR directory.
-