Re: [PATCH] perf intel-pt: Synthesize cycle events

[Adrian Hunter]

On 16.3.2022 10.19, Steinar H. Gunderson wrote:
> On Tue, Mar 15, 2022 at 10:11:54PM +0200, Adrian Hunter wrote:
>> Sorry, my first suggestion has issues, but the second is better.
> 
> I tried your second one, but can't see much difference. The original and
> your patched version still differ by a lot, and I still see various
> non-branch instructions getting very tiny fractions. (PSB packets
> _might_ be it, as there are ~1000 of them in the 165M-cycle trace.)
> 
> I guess the good news is that the perf report coming out of your version
> looks more likely to me; I have some functions that are around 1% that
> shouldn't intuitively be that much (and, if I write some Perl to sum up
> the cycles from the IPC lines in perf script, are more around 0.1%).
> So perhaps we should stop chasing the difference? I don't know.

That doesn't sound right.  I will look at it more closely in the next few days.