fio2gnuplot: Don't truncate fio log files

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index b1dcd296d700abbb14a2c50d7146c5668aa686ba..a2de47067cdd11ba4ca541cae8e46910c083cda6 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -568,6 +568,8 @@ ioengine=str        Defines how the job issues io to the file. The following
 
                        vsync   Basic readv(2) or writev(2) IO.
 
+                       psyncv  Basic preadv(2) or pwritev(2) IO.
+
                        libaio  Linux native asynchronous io. Note that Linux
                                may only support queued behaviour with
                                non-buffered IO (set direct=1 or buffered=0).
@@ -828,11 +830,15 @@ thinktime_spin=int
                to sleeping for the rest of the period specified by
                thinktime.
 
-thinktime_blocks
+thinktime_blocks=int
                Only valid if thinktime is set - control how many blocks
                to issue, before waiting 'thinktime' usecs. If not set,
                defaults to 1 which will make fio wait 'thinktime' usecs
-               after every block.
+               after every block. This effectively makes any queue depth
+               setting redundant, since no more than 1 IO will be queued
+               before we have to complete it and do our thinktime. In
+               other words, this setting effectively caps the queue depth
+               if the latter is larger.
 
 rate=int       Cap the bandwidth used by this job. The number is in bytes/sec,
                the normal suffix rules apply. You can use rate=500k to limit
@@ -1255,10 +1261,12 @@ lockmem=int     Pin down the specified amount of memory with mlock(2). Can
                The amount specified is per worker.
 
 exec_prerun=str        Before running this job, issue the command specified
-               through system(3).
+               through system(3). Output is redirected in a file called
+               jobname.prerun.txt.
 
 exec_postrun=str After the job completes, issue the command specified
-                though system(3).
+                though system(3). Output is redirected in a file called
+                jobname.postrun.txt.
 
 ioscheduler=str        Attempt to switch the device hosting the file to the specified
                io scheduler before running.
@@ -1430,11 +1438,20 @@ that defines them is selected.
 [netsplice] hostname=str
 [net] hostname=str The host name or IP address to use for TCP or UDP based IO.
                If the job is a TCP listener or UDP reader, the hostname is not
-               used and must be omitted.
+               used and must be omitted unless it is a valid UDP multicast
+               address.
 
 [netsplice] port=int
 [net] port=int The TCP or UDP port to bind to or connect to.
 
+[netsplice] interface=str
+[net] interface=str  The IP address of the network interface used to send or
+               receive UDP multicast
+
+[netsplice] ttl=int
+[net] ttl=int  Time-to-live value for outgoing UDP multicast packets.
+               Default: 1
+
 [netsplice] nodelay=bool
 [net] nodelay=bool     Set TCP_NODELAY on TCP connections.
 
@@ -1455,7 +1472,7 @@ that defines them is selected.
 [net] listen   For TCP network connections, tell fio to listen for incoming
                connections rather than initiating an outgoing connection. The
                hostname must be omitted if this option is used.
-[net] pingpong Normal a network writer will just continue writing data, and
+[net] pingpong Normaly a network writer will just continue writing data, and
                a network reader will just consume packages. If pingpong=1
                is set, a writer will send its normal payload to the reader,
                then wait for the reader to send the same payload back. This
@@ -1463,6 +1480,9 @@ that defines them is selected.
                and completion latencies then measure local time spent
                sending or receiving, and the completion latency measures
                how long it took for the other end to receive and send back.
+               For UDP multicast traffic pingpong=1 should only be set for a
+               single reader when multiple readers are listening to the same
+               address.
 
 [e4defrag] donorname=str
                File will be used as a block donor(swap extents between files)