* Wangnan (F) <[email protected]> wrote:
> >perf cmdline is
> >
> ># ./pref record -g -F 9 --call-graph dwarf ./test_dwarf_unwind
> >
> >Use default events, precise_ip == 2 so uses PEBS.
> >
>
> Testetd 'cycles', 'cycles:p' and 'cycles:pp'. Only 'cycles:pp' captures
> sample at callq. So maybe a PEBS problem?
Well, that's how our PEBS sampling works: we roll back the instruction pointer
to
point at the instruction generating the sample. The state itself is
post-instruction.
So dwarf unwind has to take this into account. Should the kernel pass in the
original (uncorrected) RIP as well, perhaps?
Thanks,
Ingo
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