On 03/30/2011 03:36 PM, Gleb Natapov wrote:
> > It's wierd. Do you get perf hits in the copying? > How can I check. The memcpy is inlined.
perf annotate x86_emulate_instruction (newer perf allows you to get there interactively from 'perf report')
> Copying a couple of hot cache lines shouldn't take any measurable > time compared to a heavyweight exit. > The whole function takes only 1.5% CPU. Perf measures how much this function become faster and heavyweight exit is not part of the function.
It's still relative to exit cost. If the total exit was 2 us, then a 1% decrease in cost translates to 40 ns.
(well, that's not unlikely for a 256 byte memcpy, but let's be sure). -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
