[PATCH] Add support for multiple jobs on the command line

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index fd9468c7b6a1faac4b9b4935702ec19b0a8870c3..ae19834f84fccd56f86feab0c2a9abf0b99c897f 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -82,6 +82,18 @@ more than one job file on the command line, fio will serialize the running
 of those files. Internally that is the same as using the 'stonewall'
 parameter described the the parameter section.
 
+If the job file contains only one job, you may as well just give the
+parameters on the command line. The command line parameters are identical
+to the job parameters, with a few extra that control global parameters
+(see README). For example, for the job file parameter iodepth=2, the
+mirror command line option would be --iodepth 2 or --iodepth=2. You can
+also use the command line for giving more than one job entry. For each
+--name option that fio sees, it will start a new job with that name.
+Command line entries following a --name entry will apply to that job,
+until there are no more entries or a new --name entry is seen. This is
+similar to the job file options, where each option applies to the current
+job until a new [] job entry is seen.
+
 fio does not need to run as root, except if the files or devices specified
 in the job section requires that. Some other options may also be restricted,
 such as memory locking, io scheduler switching, and descreasing the nice value.
@@ -115,7 +127,11 @@ size=128m
 
 As you can see, the job file sections themselves are empty as all the
 described parameters are shared. As no filename= option is given, fio
-makes up a filename for each of the jobs as it sees fit.
+makes up a filename for each of the jobs as it sees fit. On the command
+line, this job would look as follows:
+
+$ fio --name=global --rw=randread --size=128m --name=job1 --name=job2
+
 
 Lets look at an example that have a number of processes writing randomly
 to files.
@@ -136,7 +152,11 @@ Here we have no global section, as we only have one job defined anyway.
 We want to use async io here, with a depth of 4 for each file. We also
 increased the buffer size used to 32KiB and define numjobs to 4 to
 fork 4 identical jobs. The result is 4 processes each randomly writing
-to their own 64MiB file.
+to their own 64MiB file. Instead of using the above job file, you could
+have given the parameters on the command line. For this case, you would
+specify:
+
+$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
 
 fio ships with a few example job files, you can also look there for
 inspiration.
@@ -166,7 +186,9 @@ parameters.
 
 name=str       ASCII name of the job. This may be used to override the
                name printed by fio for this job. Otherwise the job
-               name is used.
+               name is used. On the command line this parameter has the
+               special purpose of also signalling the start of a new
+               job.
 
 directory=str  Prefix filenames with this directory. Used to places files
                in a different location than "./".
@@ -369,9 +391,10 @@ zoneskip=siint     Skip the specified number of bytes when zonesize data has
                been read. The two zone options can be used to only do
                io on zones of a file.
 
-write_iolog=str        Write the issued io patterns to the specified file. See iolog.
+write_iolog=str        Write the issued io patterns to the specified file. See
+               read_iolog.
 
-iolog=str      Open an iolog with the specified file name and replay the
+read_iolog=str Open an iolog with the specified file name and replay the
                io patterns it contains. This can be used to store a
                workload and replay it sometime later.