X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=d3f957bf4db7ecdeab63bfc5f38bbbd8150881be;hb=6e8136d10c903b9aab0f9159077890a68ee46dd9;hp=342bad803ac56adc062a153a74543a5d77f85f7c;hpb=44c82dba75d26d3445757d25d59fe87a056a5409;p=fio.git

diff --git a/HOWTO b/HOWTO
index 342bad80..d3f957bf 100644
--- 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