Ensure that we honor aio_read/write() returning EAGAIN

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index e8fbd97f6ab2693920b93101e654873005516f3a..ee899b8fdb6c402814086dde41f986d152c456c9 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -348,11 +348,25 @@ kb_base=int       The base unit for a kilobyte. The defacto base is 2^10, 1024.
 randrepeat=bool        For random IO workloads, seed the generator in a predictable
                way so that results are repeatable across repetitions.
 
-fallocate=bool By default, fio will use fallocate() to advise the system
-               of the size of the file we are going to write. This can be
-               turned off with fallocate=0. May not be available on all
-               supported platforms.  If using ZFS on Solaris this must be
-               set to 0 because ZFS doesn't support it.
+use_os_rand=bool Fio can either use the random generator supplied by the OS
+               to generator random offsets, or it can use it's own internal
+               generator (based on Tausworthe). Default is to use the
+               internal generator, which is often of better quality and
+               faster.
+
+fallocate=str  Whether pre-allocation is performed when laying down files.
+               Accepted values are:
+
+                       none            Do not pre-allocate space
+                       posix           Pre-allocate via posix_fallocate()
+                       keep            Pre-allocate via fallocate() with
+                                       FALLOC_FL_KEEP_SIZE set
+                       0               Backward-compatible alias for 'none'
+                       1               Backward-compatible alias for 'posix'
+
+               May not be available on all supported platforms. 'keep' is only
+               available on Linux.If using ZFS on Solaris this must be set to
+               'none' because ZFS doesn't support it. Default: 'posix'.
 
 fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
                on what IO patterns it is likely to issue. Sometimes you
@@ -375,7 +389,8 @@ filesize=int        Individual file sizes. May be a range, in which case fio
                and limited to 'size' in total (if that is given). If not
                given, each created file is the same size.
 
-fill_device=bool Sets size to something really large and waits for ENOSPC (no
+fill_device=bool
+fill_fs=bool   Sets size to something really large and waits for ENOSPC (no
                space left on device) as the terminating condition. Only makes
                 sense with sequential write. For a read workload, the mount
                point will be filled first then IO started on the result. This