> From: Stephen Hemminger [mailto:step...@networkplumber.org] > Sent: Wednesday, 27 July 2022 21.12 [RFC v2] non-temporal memcpy > > On Wed, 27 Jul 2022 20:49:59 +0200 > Morten Brørup <m...@smartsharesystems.com> wrote: > > > I'm considering rte_memcpy_nt() a performance optimized variant of > memcpy(), where the performance gain is less cache pollution. Thus, > silent fallback to memcpy() should suffice. > > > Have you looked at existing Glibc code? last time I checked it was > already doing > non-temporal instructions on several architectures.
Good idea! I found the glibc implementation of memcpy() [1], and it only uses non-temporal store, not non-temporal load; and only for big lengths. BTW, this also reveals that memcpy() sometimes behaves differently than rte_memcpy(), which never uses non-temporal store. [1] https://elixir.bootlin.com/glibc/latest/source/sysdeps/x86_64/multiarch/memcpy-ssse3.S
