backend: do_dry_run(): get_io_u() can return an error pointer

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 5e4cd4ff2663df1bff00eabcdf7382673cc5a453..85eb0fe981b0d0b89c40e9b714f48f9112778f25 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -247,6 +247,11 @@ will be used if no other format specifier is given.
 .RE
 .P
 .TP
 .RE
 .P
 .TP

+.BI unique_filename \fR=\fPbool
+To avoid collisions between networked clients, fio defaults to prefixing
+any generated filenames (with a directory specified) with the source of
+the client connecting. To disable this behavior, set this option to 0.
+.TP

 .BI lockfile \fR=\fPstr
 Fio defaults to not locking any files before it does IO to them. If a file or
 file descriptor is shared, fio can serialize IO to that file to make the end
 .BI lockfile \fR=\fPstr
 Fio defaults to not locking any files before it does IO to them. If a file or
 file descriptor is shared, fio can serialize IO to that file to make the end


@@ -304,6 +309,7 @@ Trim and write mixed workload. Blocks will be trimmed first, then the same
 blocks will be written to.
 .RE
 .P
 blocks will be written to.
 .RE
 .P

+Fio defaults to read if the option is not specified.

 For mixed I/O, the default split is 50/50. For certain types of io the result
 may still be skewed a bit, since the speed may be different. It is possible to
 specify a number of IO's to do before getting a new offset, this is done by
 For mixed I/O, the default split is 50/50. For certain types of io the result
 may still be skewed a bit, since the speed may be different. It is possible to
 specify a number of IO's to do before getting a new offset, this is done by


@@ -597,6 +603,7 @@ position the I/O location.
 .TP
 .B psync
 Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.
 .TP
 .B psync
 Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.

+Default on all supported operating systems except for Windows.

 .TP
 .B vsync
 Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by
 .TP
 .B vsync
 Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by


@@ -618,7 +625,7 @@ POSIX asynchronous I/O using \fBaio_read\fR\|(3) and \fBaio_write\fR\|(3).
 Solaris native asynchronous I/O.
 .TP
 .B windowsaio
 Solaris native asynchronous I/O.
 .TP
 .B windowsaio

-Windows native asynchronous I/O.
+Windows native asynchronous I/O. Default on Windows.

 .TP
 .B mmap
 File is memory mapped with \fBmmap\fR\|(2) and data copied using
 .TP
 .B mmap
 File is memory mapped with \fBmmap\fR\|(2) and data copied using


@@ -628,9 +635,6 @@ File is memory mapped with \fBmmap\fR\|(2) and data copied using
 \fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
 transfer data from user-space to the kernel.
 .TP
 \fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
 transfer data from user-space to the kernel.
 .TP

-.B syslet-rw
-Use the syslet system calls to make regular read/write asynchronous.
-.TP

 .B sg
 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
 the target is an sg character device, we use \fBread\fR\|(2) and
 .B sg
 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
 the target is an sg character device, we use \fBread\fR\|(2) and


@@ -652,7 +656,8 @@ and send/receive. This ioengine defines engine specific options.
 .TP
 .B cpuio
 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
 .TP
 .B cpuio
 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and

-\fBcpucycles\fR parameters.
+\fBcpuchunks\fR parameters. A job never finishes unless there is at least one
+non-cpuio job.

 .TP
 .B guasi
 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
 .TP
 .B guasi
 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface


@@ -1147,7 +1152,7 @@ Allocation method for I/O unit buffer.  Allowed values are:
 .RS
 .TP
 .B malloc
 .RS
 .TP
 .B malloc

-Allocate memory with \fBmalloc\fR\|(3).
+Allocate memory with \fBmalloc\fR\|(3). Default memory type.

 .TP
 .B shm
 Use shared memory buffers allocated through \fBshmget\fR\|(2).
 .TP
 .B shm
 Use shared memory buffers allocated through \fBshmget\fR\|(2).


@@ -1690,13 +1695,13 @@ Some parameters are only valid when a specific ioengine is in use. These are
 used identically to normal parameters, with the caveat that when used on the
 command line, they must come after the ioengine.
 .TP
 used identically to normal parameters, with the caveat that when used on the
 command line, they must come after the ioengine.
 .TP

-.BI (cpu)cpuload \fR=\fPint
+.BI (cpuio)cpuload \fR=\fPint

 Attempt to use the specified percentage of CPU cycles.
 .TP
 Attempt to use the specified percentage of CPU cycles.
 .TP

-.BI (cpu)cpuchunks \fR=\fPint
+.BI (cpuio)cpuchunks \fR=\fPint

 Split the load into cycles of the given time. In microseconds.
 .TP
 Split the load into cycles of the given time. In microseconds.
 .TP

-.BI (cpu)exit_on_io_done \fR=\fPbool
+.BI (cpuio)exit_on_io_done \fR=\fPbool

 Detect when IO threads are done, then exit.
 .TP
 .BI (libaio)userspace_reap
 Detect when IO threads are done, then exit.
 .TP
 .BI (libaio)userspace_reap


@@ -1707,7 +1712,7 @@ from user-space to reap events. The reaping mode is only
 enabled when polling for a minimum of 0 events (eg when
 iodepth_batch_complete=0).
 .TP
 enabled when polling for a minimum of 0 events (eg when
 iodepth_batch_complete=0).
 .TP

-.BI (psyncv2)hipri
+.BI (pvsync2)hipri

 Set RWF_HIPRI on IO, indicating to the kernel that it's of
 higher priority than normal.
 .TP
 Set RWF_HIPRI on IO, indicating to the kernel that it's of
 higher priority than normal.
 .TP


@@ -2082,7 +2087,7 @@ This format is not supported in Fio versions => 1.20-rc3.
 .B Trace file format v2
 .RS
 The second version of the trace file format was added in Fio version 1.17.
 .B Trace file format v2
 .RS
 The second version of the trace file format was added in Fio version 1.17.

-It allows to access more then one file per trace and has a bigger set of
+It allows one to access more then one file per trace and has a bigger set of

 possible file actions.
 
 The first line of the trace file has to be:
 possible file actions.
 
 The first line of the trace file has to be: