| Message ID | 1515778644-59547-1-git-send-email-bhanuprakash.bodireddy@intel.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [ovs-dev] doc: Update configure section with popcnt details. | expand |
On Fri, Jan 12, 2018 at 05:37:24PM +0000, Bhanuprakash Bodireddy wrote: > Popcnt instruction can be used to speedup hash computation on processors > with POPCNT support. > > Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> Applied, thanks!
diff --git a/Documentation/intro/install/general.rst b/Documentation/intro/install/general.rst index 1485bdc..718e5c2 100644 --- a/Documentation/intro/install/general.rst +++ b/Documentation/intro/install/general.rst @@ -265,6 +265,12 @@ intrinsics can be used by passing ``-msse4.2``:: $ ./configure CFLAGS="-g -O2 -msse4.2"` +Also builtin popcnt instruction can be used to speedup the counting of the +bits set in an integer. For example on X86_64 with POPCNT support, it can be +enabled by passing ``-mpopcnt``:: + + $ ./configure CFLAGS="-g -O2 -mpopcnt"` + If you are on a different processor and don't know what flags to choose, it is recommended to use ``-march=native`` settings::
Popcnt instruction can be used to speedup hash computation on processors with POPCNT support. Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> --- Documentation/intro/install/general.rst | 6 ++++++ 1 file changed, 6 insertions(+)