X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;ds=sidebyside;f=HOWTO;h=922db2f06601cab8f346c84b4e448b0745bca7f1;hb=4f5d1526bed98cde56829f9e5e040c6601c03236;hp=eb8f453ca309b156d279ce1c7a678cefccb6eb6b;hpb=23d2461974c334d77eb7a06a2dbd1f37aeee85d4;p=fio.git

diff --git a/HOWTO b/HOWTO
index eb8f453c..922db2f0 100644
--- a/HOWTO
+++ b/HOWTO
@@ -203,7 +203,13 @@ $ncpus		Number of online available CPUs
 
 These can be used on the command line or in the job file, and will be
 automatically substituted with the current system values when the job
-is run.
+is run. Simple math is also supported on these keywords, so you can
+perform actions like:
+
+size=8*$mb_memory
+
+and get that properly expanded to 8 times the size of memory in the
+machine.
 
 
 5.0 Detailed list of parameters
@@ -318,6 +324,11 @@ kb_base=int	The base unit for a kilobyte. The defacto base is 2^10, 1024.
 randrepeat=bool	For random IO workloads, seed the generator in a predictable
 		way so that results are repeatable across repetitions.
 
+fallocate=bool	By default, fio will use fallocate() to advise the system
+		of the size of the file we are going to write. This can be
+		turned off with fallocate=0. May not be available on all
+		supported platforms.
+
 fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
 		on what IO patterns it is likely to issue. Sometimes you
 		want to test specific IO patterns without telling the
@@ -555,8 +566,24 @@ 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.
 
-fsyncdata=int	Like fsync= but uses fdatasync() to only sync data and not
+fdatasync=int	Like fsync= but uses fdatasync() to only sync data and not
 		metadata blocks.
+		In FreeBSD there is no fdatasync(), this falls back to
+		using fsync()
+
+sync_file_range=str:val	Use sync_file_range() for every 'val' number of
+		write operations. Fio will track range of writes that
+		have happened since the last sync_file_range() call. 'str'
+		can currently be one or more of:
+
+		wait_before	SYNC_FILE_RANGE_WAIT_BEFORE
+		write		SYNC_FILE_RANGE_WRITE
+		wait_after	SYNC_FILE_RANGE_WAIT_AFTER
+
+		So if you do sync_file_range=wait_before,write:8, fio would
+		use SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE for
+		every 8 writes. Also see the sync_file_range(2) man page.
+		This option is Linux specific.
 
 overwrite=bool	If true, writes to a file will always overwrite existing
 		data. If the file doesn't already exist, it will be
@@ -823,7 +850,11 @@ verify=str	If writing to a file, fio can verify the file contents
 
 		This option can be used for repeated burn-in tests of a
 		system to make sure that the written data is also
-		correctly read back.
+		correctly read back. If the data direction given is
+		a read or random read, fio will assume that it should
+		verify a previously written file. If the data direction
+		includes any form of write, the verify will be of the
+		newly written data.
 
 verifysort=bool	If set, fio will sort written verify blocks when it deems
 		it faster to read them back in a sorted manner. This is
@@ -842,13 +873,14 @@ verify_interval=int	Write the verification header at a finer granularity
 			size of header_interval. blocksize should divide this
 			evenly.
 
-verify_pattern=int	If set, fio will fill the io buffers with this
+verify_pattern=str	If set, fio will fill the io buffers with this
 		pattern. Fio defaults to filling with totally random
 		bytes, but sometimes it's interesting to fill with a known
 		pattern for io verification purposes. Depending on the
 		width of the pattern, fio will fill 1/2/3/4 bytes of the
-		buffer at the time. The verify_pattern cannot be larger than
-		a 32-bit quantity.
+		buffer at the time(it can be either a decimal or a hex number).
+		The verify_pattern if larger than a 32-bit quantity has to
+		be a hex number that starts with either "0x" or "0X".
 
 verify_fatal=bool	Normally fio will keep checking the entire contents
 		before quitting on a block verification failure. If this
@@ -983,6 +1015,7 @@ gtod_cpu=int	Sometimes it's cheaper to dedicate a single thread of
 		for doing these time calls will be excluded from other
 		uses. Fio will manually clear it from the CPU mask of other
 		jobs.
+
 continue_on_error=bool	Normally fio will exit the job on the first observed
 		failure. If this option is set, fio will continue the job when
 		there is a 'non-fatal error' (EIO or EILSEQ) until the runtime
@@ -992,6 +1025,27 @@ continue_on_error=bool	Normally fio will exit the job on the first observed
 		given in the stats is the first error that was hit during the
 		run.
 
+cgroup=str	Add job to this control group. If it doesn't exist, it will
+		be created. The system must have a mounted cgroup blkio
+		mount point for this to work. If your system doesn't have it
+		mounted, you can do so with:
+
+		# mount -t cgroup -o blkio none /cgroup
+
+cgroup_weight=int	Set the weight of the cgroup to this value. See
+		the documentation that comes with the kernel, allowed values
+		are in the range of 100..1000.
+
+cgroup_nodelete=bool Normally fio will delete the cgroups it has created after
+		the job completion. To override this behavior and to leave
+		cgroups around after the job completion, set cgroup_nodelete=1.
+		This can be useful if one wants to inspect various cgroup
+		files after job completion. Default: false
+
+uid=int		Instead of running as the invoking user, set the user ID to
+		this value before the thread/process does any work.
+
+gid=int		Set group ID, see uid.
 
 6.0 Interpreting the output
 ---------------------------