More random fixes

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index ca095a322895be3065081db5bd600fb12609f3e7..d8c6b9414eef85be48779d7018682cf2bbd07470 100644 (file)
--- 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