X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=7cab05379f612034abdc173f03acb8d7850f902f;hp=8e873ea5117628b18089f86cfa0e38fbeb2a0ccd;hb=946ff86535e86f9b1be618bd4b8ae925343f1df3;hpb=72fbda2ac0b5fe8e9f3920ec7b2fd69989e50a56

diff --git a/HOWTO b/HOWTO
index 8e873ea5..7cab0537 100644
--- a/HOWTO
+++ b/HOWTO
@@ -228,11 +228,25 @@ rw=str		Type of io pattern. Accepted values are:
 
 		For the mixed io types, the default is to split them 50/50.
 		For certain types of io the result may still be skewed a bit,
-		since the speed may be different.
+		since the speed may be different. It is possible to specify
+		a number of IO's to do before getting a new offset - this
+		is only useful for random IO, where fio would normally
+		generate a new random offset for every IO. If you append
+		eg 8 to randread, you would get a new random offset for
+		every 8 IO's. The result would be a seek for only every 8
+		IO's, instead of for every IO. Use rw=randread:8 to specify
+		that.
 
 randrepeat=bool	For random IO workloads, seed the generator in a predictable
 		way so that results are repeatable across repetitions.
 
+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
+		kernel about it, in which case you can disable this option.
+		If set, fio will use POSIX_FADV_SEQUENTIAL for sequential
+		IO and POSIX_FADV_RANDOM for random IO.
+
 size=siint	The total size of file io for this job. This may describe
 		the size of the single file the job uses, or it may be
 		divided between the number of files in the job. If the
@@ -330,6 +344,14 @@ ioengine=str	Defines how the job issues io to the file. The following
 				will cause that job to do nothing but burn
 				85% of the CPU.
 
+			guasi	The GUASI IO engine is the Generic Userspace
+				Asyncronous Syscall Interface approach
+				to async IO. See
+
+				http://www.xmailserver.org/guasi-lib.html
+
+				for more info on GUASI.
+
 			external Prefix to specify loading an external
 				IO engine object file. Append the engine
 				filename, eg ioengine=external:/tmp/foo.o
@@ -533,13 +555,31 @@ verify=str	If writing to a file, fio can verify the file contents
 			crc32	Use a crc32 sum of the data area and store
 				it in the header of each block.
 
+			null	Only pretend to verify. Useful for testing
+				internals with ioengine=null, not for much
+				else.
+
 		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.
 
+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
+		often the case when overwriting an existing file, since
+		the blocks are already laid out in the file system. You
+		can ignore this option unless doing huge amounts of really
+		fast IO where the red-black tree sorting CPU time becomes
+		significant.
+		
 stonewall	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.
+		points in the job file. A stone wall also implies starting
+		a new reporting group.
+
+new_group	Start a new reporting group. If this option isn't given,
+		jobs in a file will be part of the same reporting group
+		unless seperated by a stone wall (or if it's a group
+		by itself, with the numjobs option).
 
 numjobs=int	Create the specified number of clones of this job. May be
 		used to setup a larger number of threads/processes doing