Make switch_ioscheduler() return 0 if FIO_HAVE_IOSCHED_SWITCH is undefined

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 67fd83376fd3beffe1bf62e0e204981f2815eff9..2c5896d2c212149e65c108f931a589bc681aca29 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -329,18 +329,15 @@ directory=str     Prefix filenames with this directory. Used to place files
 filename=str   Fio normally makes up a filename based on the job name,
                thread number, and file number. If you want to share
                files between threads in a job or several jobs, specify
 filename=str   Fio normally makes up a filename based on the job name,
                thread number, and file number. If you want to share
                files between threads in a job or several jobs, specify

-               a filename for each of them to override the default. If
-               the ioengine used is 'net', the filename is the host, port,
-               and protocol to use in the format of =host,port,protocol.
-               See ioengine=net for more. If the ioengine is file based, you
-               can specify a number of files by separating the names with a
-               ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
-               as the two working files, you would use
-               filename=/dev/sda:/dev/sdb. On Windows, disk devices are
-               accessed as \\.\PhysicalDrive0 for the first device,
-               \\.\PhysicalDrive1 for the second etc. Note: Windows and
-               FreeBSD prevent write access to areas of the disk containing
-               in-use data (e.g. filesystems).
+               a filename for each of them to override the default.
+               If the ioengine is file based, you can specify a number of
+               files by separating the names with a ':' colon. So if you
+               wanted a job to open /dev/sda and /dev/sdb as the two working
+               files, you would use filename=/dev/sda:/dev/sdb. On Windows,
+               disk devices are accessed as \\.\PhysicalDrive0 for the first
+               device, \\.\PhysicalDrive1 for the second etc. Note: Windows
+               and FreeBSD prevent write access to areas of the disk
+               containing in-use data (e.g. filesystems).

                If the wanted filename does need to include a colon, then
                escape that with a '\' character. For instance, if the filename
                is "/dev/dsk/foo@3,0:c", then you would use
                If the wanted filename does need to include a colon, then
                escape that with a '\' character. For instance, if the filename
                is "/dev/dsk/foo@3,0:c", then you would use


@@ -408,6 +405,7 @@ rw=str              Type of io pattern. Accepted values are:
                        trimwrite       Mixed trims and writes. Blocks will be
                                        trimmed first, then written to.
 
                        trimwrite       Mixed trims and writes. Blocks will be
                                        trimmed first, then written to.
 

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

                For the mixed io types, the default is to split them 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
                For the mixed io types, the default is to split them 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


@@ -702,7 +700,8 @@ ioengine=str        Defines how the job issues io to the file. The following
                        sync    Basic read(2) or write(2) io. lseek(2) is
                                used to position the io location.
 
                        sync    Basic read(2) or write(2) io. lseek(2) is
                                used to position the io location.
 

-                       psync   Basic pread(2) or pwrite(2) io.
+                       psync   Basic pread(2) or pwrite(2) io. Default on all
+                               supported operating systems except for Windows.

 
                        vsync   Basic readv(2) or writev(2) IO.
 
 
                        vsync   Basic readv(2) or writev(2) IO.
 


@@ -720,6 +719,7 @@ ioengine=str        Defines how the job issues io to the file. The following
                        solarisaio Solaris native asynchronous io.
 
                        windowsaio Windows native asynchronous io.
                        solarisaio Solaris native asynchronous io.
 
                        windowsaio Windows native asynchronous io.

+                               Default on Windows.

 
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).
 
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).


@@ -752,12 +752,13 @@ ioengine=str      Defines how the job issues io to the file. The following
 
                        cpuio   Doesn't transfer any data, but burns CPU
                                cycles according to the cpuload= and
 
                        cpuio   Doesn't transfer any data, but burns CPU
                                cycles according to the cpuload= and

-                               cpucycle= options. Setting cpuload=85
+                               cpuchunks= options. Setting cpuload=85

                                will cause that job to do nothing but burn
                                85% of the CPU. In case of SMP machines,
                                use numjobs=<no_of_cpu> to get desired CPU
                                usage, as the cpuload only loads a single
                                will cause that job to do nothing but burn
                                85% of the CPU. In case of SMP machines,
                                use numjobs=<no_of_cpu> to get desired CPU
                                usage, as the cpuload only loads a single

-                               CPU at the desired rate.
+                               CPU at the desired rate. A job never finishes
+                               unless there is at least one non-cpuio job.

 
                        guasi   The GUASI IO engine is the Generic Userspace
                                Asyncronous Syscall Interface approach
 
                        guasi   The GUASI IO engine is the Generic Userspace
                                Asyncronous Syscall Interface approach


@@ -1067,7 +1068,8 @@ nice=int  Run the job with the given nice value. See man nice(2).
 
 prio=int       Set the io priority value of this job. Linux limits us to
                a positive value between 0 and 7, with 0 being the highest.
 
 prio=int       Set the io priority value of this job. Linux limits us to
                a positive value between 0 and 7, with 0 being the highest.

-               See man ionice(1).
+               See man ionice(1). Refer to an appropriate manpage for
+               other operating systems since meaning of priority may differ.

 
 prioclass=int  Set the io priority class. See man ionice(1).
 
 
 prioclass=int  Set the io priority class. See man ionice(1).
 


@@ -1223,6 +1225,7 @@ mem=str           Fio can use various types of memory as the io unit buffer.
                The allowed values are:
 
                        malloc  Use memory from malloc(3) as the buffers.
                The allowed values are:
 
                        malloc  Use memory from malloc(3) as the buffers.

+                               Default memory type.

 
                        shm     Use shared memory as the buffers. Allocated
                                through shmget(2).
 
                        shm     Use shared memory as the buffers. Allocated
                                through shmget(2).


@@ -1837,12 +1840,12 @@ that defines them is selected.
 [psyncv2] hipri                Set RWF_HIPRI on IO, indicating to the kernel that
                        it's of higher priority than normal.
 
 [psyncv2] hipri                Set RWF_HIPRI on IO, indicating to the kernel that
                        it's of higher priority than normal.
 

-[cpu] cpuload=int Attempt to use the specified percentage of CPU cycles.
+[cpuio] cpuload=int Attempt to use the specified percentage of CPU cycles.

 
 

-[cpu] cpuchunks=int Split the load into cycles of the given time. In
+[cpuio] cpuchunks=int Split the load into cycles of the given time. In

                microseconds.
 
                microseconds.
 

-[cpu] exit_on_io_done=bool Detect when IO threads are done, then exit.
+[cpuio] exit_on_io_done=bool Detect when IO threads are done, then exit.

 
 [netsplice] hostname=str
 [net] hostname=str The host name or IP address to use for TCP or UDP based IO.
 
 [netsplice] hostname=str
 [net] hostname=str The host name or IP address to use for TCP or UDP based IO.