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Test results for AMD Ryzen
Author: Travis Date: 2017-09-26 14:26
FWIW Aida64 reports the throughput as 1 per ~300 cycles or so, or about a miss-to-DRAM worth of latency. The testing methodology isn't clear though: were they using CLZERO repeatedly on the same address or was it a new line each time, etc.

Either way it seems very slow: if it's the same address each time you'd expect the line to just sit in L1 the whole time in the exclusive state and for it to be quite fast, and if it were different lines you'd at least expect a lot of memory parallelism to bring the time down below the 90ns or so that was recorded.

users.atw.hu/instlatx64/AuthenticAMD0800F11_K17_Zen_InstLatX64.txt

 
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