6 ms·

I concur. I wondered whether their patch hit AMDs as well. Unlikely, but not entirely impossible, at least to me after hearing news about Linus "commenting" on

• my123 7y ago
  As far as I know, HLE is not implemented on AMD processors. However, part of the fix for JCC (https://www.intel.com/content/dam/support/us/en/documents/processors/mitigations-jump-conditional-code-erratum.pdf https://www.intel.com/content/dam/support/us/en/documents/pr... ) to recover the performance loss will make other CPUs slower if separate executables aren't used for unaffected CPUs... which they won't. > The MCU prevents jump instructions from being cached in the Decoded ICache when the jump instructions cross a 32-byte boundary or when they end on a 32-byte boundary. In this context, Jump Instructionsinclude all jumptypes: conditional jump (Jcc), macro-fusedop-Jcc(where opis one ofcmp, test, add, sub, and, inc, ordec), direct unconditional jump, indirect jump, direct/indirect call, and return The workaround to lower perf loss of having jumps uncached when they are on a 32-byte boundary involves adding quite some nops... (or padding with meaningless prefixes)
  • saagarjha 7y ago
    Looks like the impact is pretty bad in certain cases: https://twitter.com/damageboy/status/1194751035136450560 https://twitter.com/damageboy/status/1194751035136450560