Re:Every 7.8μs your computer’s memory has a hiccup
by ajross on Saturday November 24, 2018 @01:21PM
(#18523279)
Taking an average is the wrong technique here. The author is trying to measure variance between equivalent code due to hardware events. I mean, on average, DRAM access is very fast! But sometimes it's not, and that's what the article is about.
And in any case on a modern x86 system that call (which is in the VDSO, it's not a syscall) just reads the TSC and scales the result. That's going to be reliable and predictable, and much faster than the DRAM refresh excursions being measured.
And in any case on a modern x86 system that call (which is in the VDSO, it's not a syscall) just reads the TSC and scales the result. That's going to be reliable and predictable, and much faster than the DRAM refresh excursions being measured.