Re: [PATCH v6 1/7] perf/core: Define the common branch type classification

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v6 1/7] perf/core: Define the common branch type classification
Date	2017-07-10 15:50 +0200
Message-ID	<u1Hey-5Fo-15@gated-at.bofh.it> (permalink)
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On Mon, Jul 10, 2017 at 08:10:50AM -0500, Segher Boessenkool wrote:

> > PERF_BR_INT is triggered by instruction "int" .
> > PERF_BR_IRQ is triggered by interrupts, traps, faults (the ring 0,3 
> > transition).
> 
> So your "PERF_BR_INT" is a system call? 

The "INT" thing has indeed been used as system call mechanism (typically
INT 80). But these days we have special purpose syscall instructions.

It could maybe be compared to the PPC "Unconditional TRAP with
immediate" where you use the immediate value as an index into a handler
vector.

> And PERF_BR_IRQ is not an interrupt request (as its name suggests),
> not what we call an "external interrupt" either; instead it is every
> interrupt that is not a system call?

It is actual interrupts, but also faults, traps and all the other
exceptions not caused by "INT" I think.

Thread

Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Michael Ellerman <mpe@ellerman.id.au> - 2017-07-10 08:10 +0200
  Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification "Jin, Yao" <yao.jin@linux.intel.com> - 2017-07-10 10:20 +0200
    Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Michael Ellerman <mpe@ellerman.id.au> - 2017-07-10 12:40 +0200
      Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification "Jin, Yao" <yao.jin@linux.intel.com> - 2017-07-10 13:50 +0200
        Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Segher Boessenkool <segher@kernel.crashing.org> - 2017-07-10 15:20 +0200
          Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification "Jin, Yao" <yao.jin@linux.intel.com> - 2017-07-10 15:30 +0200
          Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification Peter Zijlstra <peterz@infradead.org> - 2017-07-10 15:50 +0200
            Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification "Jin, Yao" <yao.jin@linux.intel.com> - 2017-07-10 16:10 +0200
              Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Michael Ellerman <mpe@ellerman.id.au> - 2017-07-11 04:30 +0200
                Re: [PATCH v6 1/7] perf/core: Define the common branch type  classification "Jin, Yao" <yao.jin@linux.intel.com> - 2017-07-11 05:10 +0200
            Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Segher Boessenkool <segher@kernel.crashing.org> - 2017-07-10 16:40 +0200
          Re: [PATCH v6 1/7] perf/core: Define the common branch type classification Michael Ellerman <mpe@ellerman.id.au> - 2017-07-11 04:20 +0200

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