Re: [PATCH 09/14] perf, x86: use LBR for PEBS IP+1 fixup

Masami Hiramatsu
2010-03-04T20:55:34Z

Peter Zijlstra wrote:
> On Thu, 2010-03-04 at 11:21 -0500, Masami Hiramatsu wrote:
>> Peter Zijlstra wrote:
>
>>> +#define perf_misc_flags(regs) \
>>> +({ int misc = 0; \
>>> + if (user_mode(regs)) \
>>> + misc |= PERF_RECORD_MISC_USER; \
>>> + else \
>>> + misc |= PERF_RECORD_MISC_KERNEL; \
>>> + if (regs->flags & PERF_EFLAGS_EXACT) \
>>> + misc |= PERF_RECORD_MISC_EXACT; \
>>> + misc; })
>>> +
>>> +#define perf_instruction_pointer(regs) ((regs)->ip)
>>
>> Hmm, why don't you use instruction_pointer() defined in asm/ptrace.h?
>> And I couldn't find any user of this macro in this patch...
>
> perf_instruction_pointer() is used in kernel/perf_event.c, and yeah I
> could have used instruction_pointer() but that's yet another wrapper.
>
> Anyway, Yanmin is poking at doing kvm-guest profiling and will likely
> rewrite all of the perf_misc() and perf_instruction_pointer() stuff
> soon.

Hmm, still I can't find where it is used (in your patches).
Anyway, would you mean that perf_instruction_pointer() will
have different implementation by Yanmin?

Thank you,

--
Masami Hiramatsu
e-mail: mhiramat@redhat.com