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