iolog: update man page for version 3

Add documentation for iolog version 3, mainly the differences between
versions 2 and 3.

Signed-off-by: Mohamad Gebai <mogeb@fb.com>
Link: https://lore.kernel.org/r/20220407174031.599117-4-mogeb@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/HOWTO.rst b/HOWTO.rst
index 0978879ce693a6c28527497c1739bd3dfcf72158..a5fa432e4b59caa4838eb24fe5687aa2a13e43c1 100644 (file)
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -4398,7 +4398,9 @@ given in bytes. The `action` can be one of these:
 
 **wait**
           Wait for `offset` microseconds. Everything below 100 is discarded.
-          The time is relative to the previous `wait` statement.
+          The time is relative to the previous `wait` statement. Note that
+          action `wait` is not allowed as of version 3, as the same behavior
+          can be achieved using timestamps.
 **read**
           Read `length` bytes beginning from `offset`.
 **write**
@@ -4411,6 +4413,31 @@ given in bytes. The `action` can be one of these:
           Trim the given file from the given `offset` for `length` bytes.
 
 
+Trace file format v3
+~~~~~~~~~~~~~~~~~~~~
+
+The third version of the trace file format was added in fio version 3.31. It
+forces each action to have a timestamp associated with it.
+
+The first line of the trace file has to be::
+
+    fio version 3 iolog
+
+Following this can be lines in two different formats, which are described below.
+
+The file management format::
+
+    timestamp filename action
+
+The file I/O action format::
+
+    timestamp filename action offset length
+
+The `timestamp` is relative to the beginning of the run (ie starts at 0). The
+`filename`, `action`, `offset` and `length`  are identical to version 2, except
+that version 3 does not allow the `wait` action.
+
+
 I/O Replay - Merging Traces
 ---------------------------
 

diff --git a/fio.1 b/fio.1
index 984106558e6fe4c942268df54722948c310fe0fd..a2ec836ff3976403d950891514e13ea3145b2ffb 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -4117,7 +4117,9 @@ given in bytes. The `action' can be one of these:
 .TP
 .B wait
 Wait for `offset' microseconds. Everything below 100 is discarded.
-The time is relative to the previous `wait' statement.
+The time is relative to the previous `wait' statement. Note that action `wait`
+is not allowed as of version 3, as the same behavior can be achieved using
+timestamps.
 .TP
 .B read
 Read `length' bytes beginning from `offset'.
@@ -4135,6 +4137,37 @@ Write `length' bytes beginning from `offset'.
 Trim the given file from the given `offset' for `length' bytes.
 .RE
 .RE
+.RE
+.TP
+.B Trace file format v3
+The third version of the trace file format was added in fio version 3.31. It
+forces each action to have a timestamp associated with it.
+.RS
+.P
+The first line of the trace file has to be:
+.RS
+.P
+"fio version 3 iolog"
+.RE
+.P
+Following this can be lines in two different formats, which are described below.
+.P
+.B
+The file management format:
+.RS
+timestamp filename action
+.P
+.RE
+.B
+The file I/O action format:
+.RS
+timestamp filename action offset length
+.P
+The `timestamp` is relative to the beginning of the run (ie starts at 0). The
+`filename`, `action`, `offset` and `length`  are identical to version 2, except
+that version 3 does not allow the `wait` action.
+.RE
+.RE
 .SH I/O REPLAY \- MERGING TRACES
 Colocation is a common practice used to get the most out of a machine.
 Knowing which workloads play nicely with each other and which ones don't is