The Spectre Mitigation Impact For Intel Ice Lake With Core i7-1065G7
For the real-world task many of you are engaged in -- code compilation -- the impact from the Spectre mitigations with Ice Lake is very minimal and likely not noticeable to end-users, but build farms could be a different story.
Facebook's Hackbench Linux kernel scheduler benchmark still shows some overhead in the kernel's scheduler performance as a result of the Spectre/SWAPGS mitigations, but the impact isn't nearly as bad as with prior microarchitectures where the Hackbench difference tended to be very dramatic.
The socket activity and context switching performance recorded by Stress-NG is no longer vastly impaired with Ice Lake. These were some of the (synthetic) tests with earlier CPUs that saw massive hits from all of the speculative execution mitigations while now the hit is quite small but still measurable.
The ctx_clock code used for measuring the time (in clocks) to perform a context switch is in much better standing with Ice Lake / Sunny Cove. With all of the mitigations on earlier CPUs, the context switch time went from commonly around 150 clocks upwards to 600~800. With this Core i7 Ice Lake mobile CPU is now just around 80 clocks for a context switch, the best we've seen out of any x86_64 CPU to date with this particular test and much better even than the earlier pre-mitigated Intel CPUs.