Messages in this thread | | | Date | Thu, 6 Apr 2017 08:58:50 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v1 1/5] perf/core: Define the common branch type classification |
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On Tue, Apr 04, 2017 at 11:18:05AM -0300, Arnaldo Carvalho de Melo wrote: > Adding the perf kernel maintainers to the CC list.
Thanks.
> Em Fri, Mar 31, 2017 at 11:18:38PM +0800, Jin Yao escreveu: > > It is often useful to know the branch types while analyzing branch > > data. For example, a call is very different from a conditional branch. > > > > Currently we have to look it up in binary while the binary may later > > not be available and even the binary is available but user has to take > > some time. It is very useful for user to check it directly in perf > > report. > > > > Perf already has support for disassembling the branch instruction > > to get the branch type. The branch type is defined in lbr.c. > > > > To keep consistent on kernel and userspace and make the classification > > more common, the patch adds the common branch type classification > > in perf_event.h. > > > > Since the disassembling of branch instruction needs some overhead, > > a new PERF_SAMPLE_BRANCH_TYPE_SAVE is introduced to indicate if it > > needs to disassemble the branch instruction and record the branch > > type.
I don't get it. Why is the kernel interface mucked with for a user-space feature?
That's wrong.
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