X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=d8c6b9414eef85be48779d7018682cf2bbd07470;hb=4906e0b57f2b8cbad02ef2428522281cf6038bdd;hp=ca095a322895be3065081db5bd600fb12609f3e7;hpb=e28218f3017e5eb156d3a4a6e7b33651dc022cea;p=fio.git

diff --git a/HOWTO b/HOWTO
index ca095a32..d8c6b941 100644
--- a/HOWTO
+++ b/HOWTO
@@ -344,6 +344,8 @@ ioengine=str	Defines how the job issues io to the file. The following
 
 			psync 	Basic pread(2) or pwrite(2) io.
 
+			vsync	Basic readv(2) or writev(2) IO.
+
 			libaio	Linux native asynchronous io.
 
 			posixaio glibc posix asynchronous io.
@@ -381,7 +383,10 @@ ioengine=str	Defines how the job issues io to the file. The following
 				cycles according to the cpuload= and
 				cpucycle= options. Setting cpuload=85
 				will cause that job to do nothing but burn
-				85% of the CPU.
+				85% of the CPU. In case of SMP machines,
+				use numjobs=<no_of_cpu> to get desired CPU
+				usage, as the cpuload only loads a single
+				CPU at the desired rate.
 
 			guasi	The GUASI IO engine is the Generic Userspace
 				Asyncronous Syscall Interface approach
@@ -402,8 +407,9 @@ iodepth=int	This defines how many io units to keep in flight against
 		concurrency.
 
 iodepth_batch=int This defines how many pieces of IO to submit at once.
-		It defaults to the same as iodepth, but can be set lower
-		if one so desires.
+		It defaults to 1 which means that we submit each IO
+		as soon as it is available, but can be raised to submit
+		bigger batches of IO at the time.
 
 iodepth_low=int	The low water mark indicating when to start filling
 		the queue again. Defaults to the same as iodepth, meaning