Update documentation on zero_buffers / scramble_buffers

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 4377052ff61ae88224f4668304c7f8a6de4874b6..20f0c093acbd8f4f783ae736540259ce451ddbe4 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -131,8 +131,8 @@ etc. This is useful for disk drives where values are often given in base 10
 values. Specifying '30GiB' will get you 30*1000^3 bytes.
 When specifying times the default suffix meaning changes, still denoting the
 base unit of the value, but accepted suffixes are 'D' (days), 'H' (hours), 'M'
-(minutes), 'S' Seconds, 'ms' milli seconds. Time values without a unit specify
-seconds.
+(minutes), 'S' Seconds, 'ms' (or msec) milli seconds, 'us' (or 'usec') micro
+seconds. Time values without a unit specify seconds.
 The suffixes are not case sensitive.
 .TP
 .I bool
@@ -166,7 +166,9 @@ character. These directories will be assigned equally distributed to job clones
 creates with \fInumjobs\fR as long as they are using generated filenames.
 If specific \fIfilename(s)\fR are set fio will use the first listed directory,
 and thereby matching the  \fIfilename\fR semantic which generates a file each
-clone if not specified, but let all clones use the same if set.
+clone if not specified, but let all clones use the same if set. See
+\fIfilename\fR for considerations regarding escaping certain characters on
+some platforms.
 .TP
 .BI filename \fR=\fPstr
 .B fio
@@ -176,7 +178,12 @@ specify a \fIfilename\fR for each of them to override the default.
 If the I/O engine is file-based, you can specify
 a number of files by separating the names with a `:' character. `\-' is a
 reserved name, meaning stdin or stdout, depending on the read/write direction
-set.
+set. On Windows, disk devices are accessed as \\.\PhysicalDrive0 for the first
+device, \\.\PhysicalDrive1 for the second etc. Note: Windows and FreeBSD
+prevent write access to areas of the disk containing in-use data
+(e.g. filesystems). If the wanted filename does need to include a colon, then
+escape that with a '\' character. For instance, if the filename is
+"/dev/dsk/foo@3,0:c", then you would use filename="/dev/dsk/foo@3,0\:c".
 .TP
 .BI filename_format \fR=\fPstr
 If sharing multiple files between jobs, it is usually necessary to have
@@ -423,6 +430,8 @@ blocksize setting.
 .TP
 .B zero_buffers
 Initialise buffers with all zeros. Default: fill buffers with random data.
+The resulting IO buffers will not be completely zeroed, unless
+\fPscramble_buffers\fR is also turned off.
 .TP
 .B refill_buffers
 If this option is given, fio will refill the IO buffers on every submit. The
@@ -833,6 +842,26 @@ may run on.  See \fBsched_setaffinity\fR\|(2).
 .BI cpus_allowed \fR=\fPstr
 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
 .TP
+.BI cpus_allowed_policy \fR=\fPstr
+Set the policy of how fio distributes the CPUs specified by \fBcpus_allowed\fR
+or \fBcpumask\fR. Two policies are supported:
+.RS
+.RS
+.TP
+.B shared
+All jobs will share the CPU set specified.
+.TP
+.B split
+Each job will get a unique CPU from the CPU set.
+.RE
+.P
+\fBshared\fR is the default behaviour, if the option isn't specified. If
+\fBsplit\fR is specified, then fio will assign one cpu per job. If not enough
+CPUs are given for the jobs listed, then fio will roundrobin the CPUs in
+the set.
+.RE
+.P
+.TP
 .BI numa_cpu_nodes \fR=\fPstr
 Set this job running on specified NUMA nodes' CPUs. The arguments allow
 comma delimited list of cpu numbers, A-B ranges, or 'all'.
@@ -985,7 +1014,7 @@ values are:
 .RS
 .RS
 .TP
-.B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1
+.B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1 xxhash
 Store appropriate checksum in the header of each block. crc32c-intel is
 hardware accelerated SSE4.2 driven, falls back to regular crc32c if
 not supported by the system.