More __must_check annotations

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 8e6e29bbc7dd98e6eb9857596c02de03ebdd0635..ea98810a211d97328232dfb593f84654cfa2f331 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -108,8 +108,8 @@ to use any ascii name you want, except 'global' which has special meaning.
 A global section sets defaults for the jobs described in that file. A job
 may override a global section parameter, and a job file may even have
 several global sections if so desired. A job is only affected by a global
-section residing above it. If the first character in a line is a ';', the
-entire line is discarded as a comment.
+section residing above it. If the first character in a line is a ';' or a
+'#', the entire line is discarded as a comment.
 
 So lets look at a really simple job file that define to threads, each
 randomly reading from a 128MiB file.
@@ -294,6 +294,13 @@ iodepth=int        This defines how many io units to keep in flight against
                job, can be overridden with a larger value for higher
                concurrency.
 
+iodepth_low=int        The low water mark indicating when to start filling
+               the queue again. Defaults to the same as iodepth, meaning
+               that fio will attempt to keep the queue full at all times.
+               If iodepth is set to eg 16 and iodepth_low is set to 4, then
+               after fio has filled the queue of 16 requests, it will let
+               the depth drain down to 4 before starting to fill it again.
+
 direct=bool    If value is true, use non-buffered io. This is usually
                O_DIRECT.