sysbench: fix memory test

In sysbench version 0.4, the tmp variable used by the memory test to
execute requests is optimized by the compiler. Caching mechanism reduces
the direct accesses to the memory increasing the transfer speed. This
leads to false timing estimations that considerably affect read and
also random write operations.

In sysbench version 1, this issue is fixed adding the volatile modifier
to the tmp variable. This prevents compiler optimizations forcing a direct
access to the memory.

The final result is a realistic transfer speed measurement.

Signed-off-by: massimo toscanelli <massimo.toscanelli@leica-geosystems.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/meta-oe/recipes-benchmark/sysbench/sysbench_0.4.12.bb b/meta-oe/recipes-benchmark/sysbench/sysbench_0.4.12.bb
index 708c71f4f..d1725dddd 100644
--- a/meta-oe/recipes-benchmark/sysbench/sysbench_0.4.12.bb
+++ b/meta-oe/recipes-benchmark/sysbench/sysbench_0.4.12.bb
@@ -8,7 +8,9 @@ inherit autotools
 
 # The project has moved from Sourceforge to Launchpad, to Github. Use the source tarball from
 # Launchpad until the next release is available from Github.
-SRC_URI = "https://launchpad.net/ubuntu/+archive/primary/+files/${BPN}_${PV}.orig.tar.gz"
+SRC_URI = "https://launchpad.net/ubuntu/+archive/primary/+files/${BPN}_${PV}.orig.tar.gz \
+           file://0001-Adding-volatile-modifier-to-tmp-variable-in-memory-t.patch \
+           "
 
 SRC_URI[md5sum] = "3a6d54fdd3fe002328e4458206392b9d"
 SRC_URI[sha256sum] = "83fa7464193e012c91254e595a89894d8e35b4a38324b52a5974777e3823ea9e"