Add 'wait_for_previous' as an alias for the 'stonewall' option

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 8b17610dd4a457438f56233d2ff5dfde80e63a61..88bd5e6c14f0f1ff356fbab964fd0a12a0a63c61 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -8,7 +8,7 @@ Table of contents
 5. Detailed list of parameters
 6. Normal output
 7. Terse output
-
+8. Trace file format
 
 1.0 Overview and history
 ------------------------
@@ -568,6 +568,11 @@ ioengine=str       Defines how the job issues io to the file. The following
 
                                for more info on GUASI.
 
+                       rdma    The RDMA I/O engine  supports  both  RDMA
+                               memory semantic(RDMA_WRITE/RDMA_READ) and
+                               channel semantic(Send/Recv) in InfiniBand, RoCE
+                               and iWarp environment.
+
                        external Prefix to specify loading an external
                                IO engine object file. Append the engine
                                filename, eg ioengine=external:/tmp/foo.o
@@ -987,7 +992,8 @@ verify_backlog_batch=int    Control how many blocks fio will verify
                if verify_backlog_batch is larger than verify_backlog, some
                blocks will be verified more than once.
                
-stonewall      Wait for preceeding jobs in the job file to exit, before
+stonewall
+wait_for_previous Wait for preceeding jobs in the job file to exit, before
                starting this one. Can be used to insert serialization
                points in the job file. A stone wall also implies starting
                a new reporting group.
@@ -1334,3 +1340,64 @@ Split up, the format is as follows:
        Additional Info (dependant on continue_on_error, default off): total # errors, first error code 
        
        Additional Info (dependant on description being set): Text description
+
+
+8.0 Trace file format
+---------------------
+There are two trace file format that you can encounter. The older (v1) format 
+is unsupported since version 1.20-rc3 (March 2008). It will still be described
+below in case that you get an old trace and want to understand it.
+
+In any case the trace is a simple text file with a single action per line.
+
+
+8.1 Trace file format v1
+------------------------
+Each line represents a single io action in the following format:
+
+rw, offset, length
+
+where rw=0/1 for read/write, and the offset and length entries being in bytes.
+
+This format is not supported in Fio versions => 1.20-rc3.
+
+
+8.2 Trace file format v2
+------------------------
+The second version of the trace file format was added in Fio version 1.17.
+It allows to access more then one file per trace and has a bigger set of
+possible file actions.
+
+The first line of the trace file has to be:
+
+fio version 2 iolog
+
+Following this can be lines in two different formats, which are described below.
+
+The file management format:
+
+filename action
+
+The filename is given as an absolute path. The action can be one of these:
+
+add          Add the given filename to the trace
+open         Open the file with the given filename. The filename has to have 
+             been added with the add action before.
+close        Close the file with the given filename. The file has to have been
+             opened before.
+
+
+The file io action format:
+
+filename action offset length
+
+The filename is given as an absolute path, and has to have been added and opened
+before it can be used with this format. The offset and length are given in 
+bytes. The action can be one of these:
+
+wait       Wait for 'offset' microseconds. Everything below 100 is discarded.
+read       Read 'length' bytes beginning from 'offset'
+write      Write 'length' bytes beginning from 'offset'
+sync       fsync() the file
+datasync   fdatasync() the file
+trim       trim the given file from the given 'offset' for 'length' bytes