Built-in CRC32 intrinsics can be used for efficient hash computation on
processors with SSE4.2 support.
Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodire...@intel.com>
---
INSTALL.md | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/INSTALL.md b/INSTALL.md
index 591f924..6fbf9ea 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -217,6 +217,21 @@ default CFLAGS plus "-mssse3", you might run configure as
follows:
`% ./configure CFLAGS="-g -O2 -mssse3"`
+For efficient hash computation special flags can be passed to leverage
+built-in intrinsics. For example on X86_64 with SSE4.2 instruction set
+support, CRC32 intrinsics can be used by passing '-msse4.2'.
+
+ `% ./configure CFLAGS="-g -O2 -msse4.2"`
+
+If you are on a different processor and don't know what flags to choose, it
+is recommended to use '-march=native' settings.
+
+ `% ./configure CFLAGS="-g -O2 -march=native"`
+
+With this, GCC will detect the processor and automatically set appropriate
+flags for it. This should not be used if you are compiling OVS outside the
+target machine.
+
Note that these CFLAGS are not applied when building the Linux
kernel module. Custom CFLAGS for the kernel module are supplied
using the EXTRA_CFLAGS variable when running make. So, for example:
--
2.4.11
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
