qemu-img bench

This adds a qemu-img command that allows doing some simple benchmarks
for the block layer without involving guest devices and a real VM.

For the start, this implements only a test of sequential reads.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/qemu-img.texi b/qemu-img.texi
index afaebdd408..b6b28e3542 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -131,6 +131,16 @@ Skip the creation of the target volume
 Command description:
 
 @table @option
+@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [-n] [-q] [-s @var{buffer_size}] [-t @var{cache}] @var{filename}
+
+Run a simple sequential read benchmark on the specified image. A total number
+of @var{count} I/O requests is performed, each @var{buffer_size} bytes in size,
+and with @var{depth} requests in parallel.
+
+If @code{-n} is specified, the native AIO backend is used if possible. On
+Linux, this option only works if @code{-t none} or @code{-t directsync} is
+specified as well.
+
 @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename}
 
 Perform a consistency check on the disk image @var{filename}. The command can