3 ms·
Yes. Mitigations drastically increase the cost of branch mispredictions, which has always been expensive on x86 and has gotten even worse. See also the sister c
by corty 6y ago
Yes. Mitigations drastically increase the cost of branch mispredictions, which has always been expensive on x86 and has gotten even worse. See also the sister comment.
Cache misses have the same problem.
- riscy 6y agoI highly doubt the author compiled Z3 with those mitigations enabled, because they are opt-in compiler options. Perhaps if the program makes frequent system calls then the kernel’s mitigations would introduce overhead.
- tyingq 6y agoMy impression is that the mitigations that would hit hardest are Intel microcode patches that load at boot time, and it may not have been obvious to revert those. Or perhaps not wise to, depending on the production environment.
- gowld 6y agoWhy? If performance matters, don't browse Reddit on your lab machine. I don't run antivirus on my microwave oven. There's no need.
- corty 6y agoSupport for most hardware depends on applying latest patches for HW and SW. Only if you explicitly bought as HPC or Lab environment with the appropriate contract specifying performance you might get around that.
- mschuster91 6y ago> I don't run antivirus on my microwave oven. There's no need. Only as long as you have not connected it to any network - "smart" appliances have often enough been used for botnets now.
- panpanna 6y ago> I don't run antivirus on my microwave oven. There's no need. Oh brother, I got some bad news for you. It's called the Mirai botnet.