Add the file sharing bits

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 3d6b354b87b7df40f723c497ab82b1424cd287f6..3e0a31b6767aadb1855471337b50bd8643767c59 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -219,6 +219,14 @@ filename=str       Fio normally makes up a filename based on the job name,
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 
+lockfile=bool  If set, fio will lock a file internally before doing IO to it.
+               This makes it safe to share file descriptors across fio
+               jobs that run at the same time.
+
+lockfile_batch=int     Acquiring a semaphore can be quite expensive, so
+               allow a process to complete this number of IOs before releasing
+               the semaphore again. Defaults to 1.
+
 readwrite=str
 rw=str         Type of io pattern. Accepted values are:
 
@@ -344,7 +352,7 @@ 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(3) IO.
+                       vsync   Basic readv(2) or writev(2) IO.
 
                        libaio  Linux native asynchronous io.
 
@@ -383,7 +391,10 @@ 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