Search found 3 matches

by jtsmith
2020-09-06, 20:35:02
Forum: Agner's CPU blog
Topic: Surprising new feature in AMD Ryzen 3000
Replies: 11
Views: 2503533

Re: Surprising new feature in AMD Ryzen 3000

What do you mean by a store expiring? Committing, draining to the cache, or being overwritten in the store buffer ring? For normal load forwarding, it's desirable to support matching as long as possible, even beyond the buffer entry already being copied to L1, to save the most bandwidth and latency ...
by jtsmith
2020-08-29, 21:48:49
Forum: Agner's CPU blog
Topic: Surprising new feature in AMD Ryzen 3000
Replies: 11
Views: 2503533

Re: Surprising new feature in AMD Ryzen 3000

I don't think there is anything that can be done about the speculation squash penalty, but I'm skeptical that compilers would emit many naturally-aliasing writes due to register allocation conservatism alone. Additionally, this renaming doesn't make much sense to employ for loads reasonably likely t...
by jtsmith
2020-08-28, 19:34:46
Forum: Agner's CPU blog
Topic: Surprising new feature in AMD Ryzen 3000
Replies: 11
Views: 2503533

Re: Surprising new feature in AMD Ryzen 3000

Although I had to double-check about the equivalence of the test cases, this "memory renaming" got noticed and examined earlier in this year by some of the usual suspects: https://gist.github.com/travisdowns/bc9af3a0aaca5399824cf182f85b9e9c https://pvk.ca/Blog/2020/02/01/too-much-locality-for-store-...