[dpdk-dev] [PATCH] eal/x86: revert select optimized memcpy at run-time

Thomas Monjalon thomas at monjalon.net
Tue Nov 7 01:15:27 CET 2017


03/11/2017 13:47, Xiaoyun Li:
> This patch reverts the patchset run-time Linking support including the
> following 3 commits:
> commit 84cc318424d4 ("eal/x86: select optimized memcpy at run-time")
> commit c7fbc80fe60f ("test: select memcpy alignment unit at run-time")
> commit 5f180ae32962 ("efd: move AVX2 lookup in its own compilation unit")
> 
> The patchset would cause perf drop in vhost/virtio loopback performance
> test. Because the run-time dispatch must cost at least a function call
> comparing to the compile-time dispatch. And the reference cpu cycles value
> is small. And in the test, when using 128-256 bytes packet, it would cause
> 16%-20% perf drop with mergeble path. When using 256 bytes packet, it would
> cause 13% perf drop with vector path.
> So revert that patchset.
> 
> Signed-off-by: Xiaoyun Li <xiaoyun.li at intel.com>

Revert applied



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