Remove comment wrt sigaction() usage, it's deprecated

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index d8c6b9414eef85be48779d7018682cf2bbd07470..12974f3f4dcc563cd143a1084aaff17116d70d48 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -219,6 +219,25 @@ filename=str       Fio normally makes up a filename based on the job name,
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 
+lockfile=str   Fio defaults to not doing any locking files before it does
+               IO to them. If a file or file descriptor is shared, fio
+               can serialize IO to that file to make the end result
+               consistent. This is usual for emulating real workloads that
+               share files. The lock modes are:
+
+                       none            No locking. The default.
+                       exclusive       Only one thread/process may do IO,
+                                       excluding all others.
+                       readwrite       Read-write locking on the file. Many
+                                       readers may access the file at the
+                                       same time, but writes get exclusive
+                                       access.
+
+               The option may be post-fixed with a lock batch number. If
+               set, then each thread/process may do that amount of IOs to
+               the file before giving up the lock. Since lock acqusition is
+               expensive, batching the lock/unlocks will speed up IO.
+
 readwrite=str
 rw=str         Type of io pattern. Accepted values are:
 
@@ -317,6 +336,12 @@ bs_unaligned       If this option is given, any byte size value within bsrange
 zero_buffers   If this option is given, fio will init the IO buffers to
                all zeroes. The default is to fill them with random data.
 
+refill_buffers If this option is given, fio will refill the IO buffers
+               on every submit. The default is to only fill it at init
+               time and reuse that data. Only makes sense if zero_buffers
+               isn't specified, naturally. If data verification is enabled,
+               refill_buffers is also automatically enabled.
+
 nrfiles=int    Number of files to use for this job. Defaults to 1.
 
 openfiles=int  Number of files to keep open at the same time. Defaults to
@@ -350,6 +375,8 @@ ioengine=str        Defines how the job issues io to the file. The following
 
                        posixaio glibc posix asynchronous io.
 
+                       solarisaio Solaris native asynchronous io.
+
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).
 
@@ -435,7 +462,11 @@ fsync=int  If writing to a file, issue a sync of the dirty data
                not sync the file. The exception is the sg io engine, which
                synchronizes the disk cache anyway.
 
-overwrite=bool If writing to a file, setup the file first and do overwrites.
+overwrite=bool If true, writes to a file will always overwrite existing
+               data. If the file doesn't already exist, it will be
+               created before the write phase begins. If the file exists
+               and is large enough for the specified write phase, nothing
+               will be done.
 
 end_fsync=bool If true, fsync file contents when the job exits.
 
@@ -443,10 +474,6 @@ fsync_on_close=bool        If true, fio will fsync() a dirty file on close.
                This differs from end_fsync in that it will happen on every
                file close, not just at the end of the job.
 
-rwmixcycle=int Value in milliseconds describing how often to switch between
-               reads and writes for a mixed workload. The default is
-               500 msecs.
-
 rwmixread=int  How large a percentage of the mix should be reads.
 
 rwmixwrite=int How large a percentage of the mix should be writes. If both
@@ -463,6 +490,12 @@ norandommap        Normally fio will cover every block of the file when doing
                fio doesn't track potential block rewrites which may alter
                the calculated checksum for that block.
 
+softrandommap  See norandommap. If fio runs with the random block map enabled
+               and it fails to allocate the map, if this option is set it
+               will continue without a random block map. As coverage will
+               not be as complete as with random maps, this option is
+               disabled by default.
+
 nice=int       Run the job with the given nice value. See man nice(2).
 
 prio=int       Set the io priority value of this job. Linux limits us to
@@ -793,6 +826,8 @@ Client1 (g=0): err= 0:
     bw (KiB/s) : min=    0, max= 1196, per=51.00%, avg=664.02, stdev=681.68
   cpu        : usr=1.49%, sys=0.25%, ctx=7969, majf=0, minf=17
   IO depths    : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0%
+     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
+     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
      issued r/w: total=0/32768, short=0/0
      lat (msec): 2=1.6%, 4=0.0%, 10=3.2%, 20=12.8%, 50=38.4%, 100=24.8%,
      lat (msec): 250=15.2%, 500=0.0%, 750=0.0%, 1000=0.0%, >=2048=0.0%
@@ -830,6 +865,11 @@ IO depths= The distribution of io depths over the job life time. The
                16= entries includes depths up to that value but higher
                than the previous entry. In other words, it covers the
                range from 16 to 31.
+IO submit=     How many pieces of IO were submitting in a single submit
+               call. Each entry denotes that amount and below, until
+               the previous entry - eg, 8=100% mean that we submitted
+               anywhere in between 5-8 ios per submit call.
+IO complete=   Like the above submit number, but for completions instead.
 IO issued=     The number of read/write requests issued, and how many
                of them were short.
 IO latencies=  The distribution of IO completion latencies. This is the