Allow explicit setting of a number of files

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index de4b0a9932b43f207260a569a5e33349efebc63b..5df2607e874a35fa131db5f36a0095af2dfe917a 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -205,7 +205,11 @@ filename=str       Fio normally makes up a filename based on the job name,
                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 and
-               port to connect to in the format of =host:port.
+               port to connect to in the format of =host:port. If the
+               ioengine is file based, you can specify a number of files
+               by seperating 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
 
 rw=str         Type of io pattern. Accepted values are:
 
@@ -253,6 +257,23 @@ bs_unaligned       If this option is given, any byte size value within bsrange
 
 nrfiles=int    Number of files to use for this job. Defaults to 1.
 
+openfiles=int  Number of files to keep open at the same time. Defaults to
+               the same as nrfiles, can be set smaller to limit the number
+               simultaneous opens.
+
+file_service_type=str  Defines how fio decides which file from a job to
+               service next. The following types are defined:
+
+                       random  Just choose a file at random.
+
+                       roundrobin  Round robin over open files. This
+                               is the default.
+
+               The string can have a number appended, indicating how
+               often to switch to a new file. So if option random:4 is
+               given, fio will switch to a new random file after 4 ios
+               have been issued.
+
 ioengine=str   Defines how the job issues io to the file. The following
                types are defined:
 
@@ -289,6 +310,17 @@ ioengine=str       Defines how the job issues io to the file. The following
                                or receive, if the latter only the port
                                argument is used.
 
+                       cpu     Doesn't transfer any data, but burns CPU
+                               cycles according to the cpuload= and
+                               cpucycle= options. Setting cpuload=85
+                               will cause that job to do nothing but burn
+                               85% of the CPU.
+
+                       external Prefix to specify loading an external
+                               IO engine object file. Append the engine
+                               filename, eg ioengine=external:/tmp/foo.o
+                               to load ioengine foo.o in /tmp.
+
 iodepth=int    This defines how many io units to keep in flight against
                the file. The default is 1 for each file defined in this
                job, can be overridden with a larger value for higher
@@ -483,7 +515,15 @@ stonewall  Wait for preceeding jobs in the job file to exit, before
 
 numjobs=int    Create the specified number of clones of this job. May be
                used to setup a larger number of threads/processes doing
-               the same thing.
+               the same thing. We regard that grouping of jobs as a
+               specific group.
+
+group_reporting        If 'numjobs' is set, it may be interesting to display
+               statistics for the group as a whole instead of for each
+               individual job. This is especially true of 'numjobs' is
+               large, looking at individual thread/process output quickly
+               becomes unwieldy. If 'group_reporting' is specified, fio
+               will show the final report per-group instead of per-job.
 
 thread         fio defaults to forking jobs, however if this option is
                given, fio will use pthread_create(3) to create threads
@@ -648,10 +688,11 @@ util=             The disk utilization. A value of 100% means we kept the disk
 ----------------
 
 For scripted usage where you typically want to generate tables or graphs
-of the results, fio can output the results in a comma separated format.
+of the results, fio can output the results in a semicolon separated format.
 The format is one long line of values, such as:
 
-client1,0,0,936,331,2894,0,0,0.000000,0.000000,1,170,22.115385,34.290410,16,714,84.252874%,366.500000,566.417819,3496,1237,2894,0,0,0.000000,0.000000,0,246,6.671625,21.436952,0,2534,55.465300%,1406.600000,2008.044216,0.000000%,0.431928%,1109
+client1;0;0;1906777;1090804;1790;0;0;0.000000;0.000000;0;0;0.000000;0.000000;929380;1152890;25.510151%;1078276.333333;128948.113404;0;0;0;0;0;0.000000;0.000000;0;0;0.000000;0.000000;0;0;0.000000%;0.000000;0.000000;100.000000%;0.000000%;324;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%;0.0%;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%
+;0.0%;0.0%;0.0%;0.0%;0.0%
 
 Split up, the format is as follows:
 
@@ -667,4 +708,7 @@ Split up, the format is as follows:
                Completion latency: min, max, mean, deviation
                Bw: min, max, aggregate percentage of total, mean, deviation
        CPU usage: user, system, context switches
+       IO depths: <=1, 2, 4, 8, 16, 32, >=64
+       IO latencies: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
+       Text description