[dpdk-dev] [PATCH v2 0/2] dpdk: Allow for dynamic enablement of some isolated features
Venky Venkatesan
venky.venkatesan at intel.com
Wed Jul 30 21:03:38 CEST 2014
Neil,
> Hey all-
> I've been trying to update the fedora dpdk package to support VFIO
> enabled drivers and ran into a problem in which ixgbe didn't compile because the
> rxtx_vec code uses sse4.2 instruction intrinsics, which aren't supported in the
> default config I have. I tried to remedy this by replacing the intrinsics with
> the __builtin macros, but it was pointed out (correctly), that this doesn't work
> properly. So this is my second attempt, which I actually like a bit better. I
> noted that code that uses intrinsics (ixgbe and the acl library), don't need to
> have those instructions turned on build-wide. Rather, we can just enable the
> instructions in the specific code we want to build with support for that, and
> test for instruction support dynamically at run time. This allows me to build
> the dpdk for a generic platform, but in such a way that some optimizations can
> be used if the executing cpu supports them at run time.
>
> Change notes:
>
> v2)
> * Added Log messages to run time check failures per Konstantin
> * Removed run time check caching in acl per Konstantin
>
> Signed-off-by: Neil Horman <nhorman at tuxdriver.com>
> CC: Thomas Monjalon <thomas.monjalon at 6wind.com>
>
One possible change to look at - the _mm_shuffle_epi8 is something that
is available all the way from SSSE3, so you should be able to leave that
in. The SSE4.2 dependency is only for the popcount (and
__builtin_popcountll will work for that anyway). That should make things
simpler.
-Venky
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