X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=cae95b7720f210893bb7b89a5b445ba61a980bf5;hb=c6dfd837e0c0e46495d57d085dc78a66cf67dfdf;hp=6d903bba0cb372745767ca7f81afcd19aefbc544;hpb=c4aa2d0825c180dd96ffff8ce1d74b967f3a0f4a;p=fio.git

diff --git a/HOWTO b/HOWTO
index 6d903bba..cae95b77 100644
--- a/HOWTO
+++ b/HOWTO
@@ -886,7 +886,8 @@ Target file/device
 	If this isn't set, fio will abort jobs that are destructive (e.g. that write)
 	to what appears to be a mounted device or partition. This should help catch
 	creating inadvertently destructive tests, not realizing that the test will
-	destroy data on the mounted file system. Default: false.
+	destroy data on the mounted file system. Note that some platforms don't allow
+	writing against a mounted device regardless of this option. Default: false.
 
 .. option:: pre_read=bool
 
@@ -1099,13 +1100,15 @@ I/O type
 	blocks given. For example, if you give 32 as a parameter, fio will sync the
 	file for every 32 writes issued. If fio is using non-buffered I/O, we may
 	not sync the file. The exception is the sg I/O engine, which synchronizes
-	the disk cache anyway.
+	the disk cache anyway. Defaults to 0, which means no sync every certain
+	number of writes.
 
 .. option:: fdatasync=int
 
 	Like :option:`fsync` but uses :manpage:`fdatasync(2)` to only sync data and
 	not metadata blocks.  In Windows, FreeBSD, and DragonFlyBSD there is no
 	:manpage:`fdatasync(2)`, this falls back to using :manpage:`fsync(2)`.
+	Defaults to 0, which means no sync data every certain number of writes.
 
 .. option:: write_barrier=int
 
@@ -1426,7 +1429,9 @@ Buffers and memory
 .. option:: invalidate=bool
 
 	Invalidate the buffer/page cache parts for this file prior to starting
-	I/O. Defaults to true.
+	I/O if the platform and file type support it. Defaults to true.
+	This will be ignored if :option:`pre_read` is also specified for the
+	same job.
 
 .. option:: sync=bool
 
@@ -1568,6 +1573,7 @@ I/O engine
 		**sync**
 			Basic :manpage:`read(2)` or :manpage:`write(2)`
 			I/O. :manpage:`lseek(2)` is used to position the I/O location.
+			See :option:`fsync` and :option:`fdatasync` for syncing write I/Os.
 
 		**psync**
 			Basic :manpage:`pread(2)` or :manpage:`pwrite(2)` I/O.  Default on
@@ -1745,7 +1751,8 @@ caveat that when used on the command line, they must come after the
 
 .. option:: cpuload=int : [cpuio]
 
-	Attempt to use the specified percentage of CPU cycles.
+	Attempt to use the specified percentage of CPU cycles. This is a mandatory
+	option when using cpuio I/O engine.
 
 .. option:: cpuchunks=int : [cpuio]
 
@@ -2590,6 +2597,12 @@ Measurements and reporting
 	all jobs in a file will be part of the same reporting group, unless
 	separated by a :option:`stonewall`.
 
+.. option:: stats
+
+	By default, fio collects and shows final output results for all jobs
+	that run. If this option is set to 0, then fio will ignore it in
+	the final stat output.
+
 .. option:: write_bw_log=str
 
 	If given, write a bandwidth log for this job. Can be used to store data of