Merge branch 'fix-infinite-loop-of-io_uring' of https://github.com/satoru-takeuchi/fio

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 45cf0bdf4b7367a870f472d23aac8e45de60e43c..4fd4da1471758c14808f1d545d33b2a267557b42 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1991,6 +1991,8 @@ I/O engine
                        Asynchronous read and write using DDN's Infinite Memory Engine (IME).
                        This engine will try to stack as much IOs as possible by creating
                        requests for IME. FIO will then decide when to commit these requests.
+               **libiscsi**
+                       Read and write iscsi lun with libiscsi.
 
 I/O engine specific parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2339,8 +2341,13 @@ I/O depth
        ``serialize_overlap`` tells fio to avoid provoking this behavior by explicitly
        serializing in-flight I/Os that have a non-zero overlap. Note that setting
        this option can reduce both performance and the :option:`iodepth` achieved.
-       Additionally this option does not work when :option:`io_submit_mode` is set to
-       offload. Default: false.
+
+       This option only applies to I/Os issued for a single job except when it is
+       enabled along with :option:`io_submit_mode`=offload. In offload mode, fio
+       will check for overlap among all I/Os submitted by offload jobs with :option:`serialize_overlap`
+       enabled.
+
+       Default: false.
 
 .. option:: io_submit_mode=str
 
@@ -2559,12 +2566,13 @@ I/O replay
 
 .. option:: replay_align=int
 
-       Force alignment of I/O offsets and lengths in a trace to this power of 2
-       value.
+       Force alignment of the byte offsets in a trace to this value. The value
+       must be a power of 2.
 
 .. option:: replay_scale=int
 
-       Scale sector offsets down by this factor when replaying traces.
+       Scale byte offsets down by this factor when replaying traces. Should most
+       likely use :option:`replay_align` as well.
 
 .. option:: replay_skip=str
 
@@ -3000,6 +3008,10 @@ Steady state
        data from the rolling collection window. Threshold limits can be expressed
        as a fixed value or as a percentage of the mean in the collection window.
 
+       When using this feature, most jobs should include the :option:`time_based`
+       and :option:`runtime` options or the :option:`loops` option so that fio does not
+       stop running after it has covered the full size of the specified file(s) or device(s).
+
                **iops**
                        Collect IOPS data. Stop the job if all individual IOPS measurements
                        are within the specified limit of the mean IOPS (e.g., ``iops:2``