[PATCH] Support for mmap of hugetlb files as memory backing

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 1176d2287f815439c680a38249a104682fcae64a..f5e2449c22d64956015d983c04c1f93aa8dc9840 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -264,6 +264,10 @@ ioengine=str       Defines how the job issues io to the file. The following
                                we use read(2) and write(2) for asynchronous
                                io.
 
+                       null    Doesn't transfer any data, just pretends
+                               to. This is mainly used to exercise fio
+                               itself and for debugging/testing purposes.
+
 iodepth=int    This defines how many io units to keep in flight against
                the file. The default is 1 for each file defined in this
                job, can be overridden with a larger value for higher
@@ -353,9 +357,15 @@ mem=str            Fio can use various types of memory as the io unit buffer.
                        shm     Use shared memory as the buffers. Allocated
                                through shmget(2).
 
+                       shmhuge Same as shm, but use huge pages as backing.
+
                        mmap    Use anonymous memory maps as the buffers.
                                Allocated through mmap(2).
 
+                       mmaphuge Use a memory mapped huge file as the buffer
+                               backing. Append filename after mmaphuge, ala
+                               mem=mmaphuge:/hugetlbfs/file
+
                The area allocated is a function of the maximum allowed
                bs size for the job, multiplied by the io depth given.