> From: Mattias Rönnblom [mailto:hof...@lysator.liu.se] > Sent: Wednesday, 10 August 2022 13.56 > > On 2022-08-09 17:26, Stephen Hemminger wrote:
[...] > > Alignment seems like a non-issue to me. A NT-store memcpy() can be made > free of alignment requirements, incurring only a very slight cost for > the always-aligned case (who has their data always 16-byte aligned > anyways?). > > The memory barrier required on x86 seems like a bigger issue. > > > Maybe rte_non_cache_copy()? > > > > rte_memcpy_nt_weakly_ordered(), or rte_memcpy_nt_weak(). And a > rte_memcpy_nt() with the sfence is place, which the user hopefully will > find first? I don't know. I would prefer not having the weak variant at > all. > > Accepting weak memory ordering (i.e., no sfence) could also be one of > the flags, assuming rte_memcpy_nt() would have a flags parameter. > Default is safe (=memcpy() semantics), but potentially slower. Excellent idea! > > > Want to avoid the naive user just doing s/memcpy/rte_memcpy_nt/ and > expect > > everything to work.
