Merge branch 'windowaio_invalidate' of https://github.com/sitsofe/fio

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 342bad803ac56adc062a153a74543a5d77f85f7c..d3f957bf4db7ecdeab63bfc5f38bbbd8150881be 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -217,6 +217,9 @@ Command line options
 .. option:: --max-jobs=nr
 
        Set the maximum number of threads/processes to support to `nr`.
+       NOTE: On Linux, it may be necessary to increase the shared-memory
+       limit ('/proc/sys/kernel/shmmax') if fio runs into errors while
+       creating jobs.
 
 .. option:: --server=args
 
@@ -1797,6 +1800,10 @@ I/O engine
                        absolute or relative. See :file:`engines/skeleton_external.c` for
                        details of writing an external I/O engine.
 
+               **filecreate**
+                       Simply create the files and do no IO to them.  You still need to
+                       set  `filesize` so that all the accounting still occurs, but no
+                       actual IO will be done other than creating the file.
 
 I/O engine specific parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2862,7 +2869,15 @@ Measurements and reporting
 
 .. option:: clat_percentiles=bool
 
-       Enable the reporting of percentiles of completion latencies.
+       Enable the reporting of percentiles of completion latencies.  This
+       option is mutually exclusive with :option:`lat_percentiles`.
+
+.. option:: lat_percentiles=bool
+
+       Enable the reporting of percentiles of IO latencies. This is similar
+       to :option:`clat_percentiles`, except that this includes the
+       submission latency. This option is mutually exclusive with
+       :option:`clat_percentiles`.
 
 .. option:: percentile_list=float_list