3 ms·

Thankfully, this doesn't seem to affect my Haswell machine. A microcode update was installed on 2021-06-09, but the microcode loader reports its build date as 2

• BeeOnRope 5y ago
  It isn't clear if Haswell has this optimization. As an easy test you could run the zero-fill-bench linked in the post and check the fill0 vs fill1 numbers. If they are the same, Haswell probably never had this optimization in the first place. Based on the Intel microcode release note [1] it doesn't seem like client HSW got any update this time, only HSX (Haswell Xeon). --- [1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/commit/3f97690f0da8011f52209b232450a1e5c4f2e1f6#diff-e6fad0f2abbac6c9603b2e8f88fe1d151a83de708aeca1c1d93d881c958ecba4 https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...
• icegreentea2 5y ago
  From the post about the original finding (https://travisdowns.github.io/blog/2020/05/13/intel-zero-opt.html https://travisdowns.github.io/blog/2020/05/13/intel-zero-opt...), it looks like Haswell did not have this optimization to begin with (find section Hardware Survey and look at the different architectures - specifically looking for divergence in performance at L3 and RAM between orange and blue dots).