[all-commits] [llvm/llvm-project] 1360e1: [llvm-exegesis] Add benchmark latency option o...

[Vy Nguyen via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1360e140cc7bf46ec4beee232c1ce4f501a6d8d2
      https://github.com/llvm/llvm-project/commit/1360e140cc7bf46ec4beee232c1ce4f501a6d8d2
  Author: Vy Nguyen <vyng at google.com>
  Date:   2020-07-16 (Thu, 16 Jul 2020)

  Changed paths:
    M llvm/docs/CommandGuide/llvm-exegesis.rst
    A llvm/test/tools/llvm-exegesis/X86/lbr/Inputs/mov_add.att
    A llvm/test/tools/llvm-exegesis/X86/lbr/lit.local.cfg
    A llvm/test/tools/llvm-exegesis/X86/lbr/mov-add.s
    M llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
    M llvm/tools/llvm-exegesis/lib/PerfHelper.cpp
    M llvm/tools/llvm-exegesis/lib/PerfHelper.h
    M llvm/tools/llvm-exegesis/lib/X86/CMakeLists.txt
    M llvm/tools/llvm-exegesis/lib/X86/Target.cpp
    A llvm/tools/llvm-exegesis/lib/X86/X86Counter.cpp
    A llvm/tools/llvm-exegesis/lib/X86/X86Counter.h
    M llvm/tools/llvm-exegesis/llvm-exegesis.cpp

  Log Message:
  -----------
      [llvm-exegesis] Add benchmark latency option on X86 that uses LBR for more precise measurements.

    Starting with Skylake, the LBR contains the precise number of cycles between the two
    consecutive branches.
    Making use of this will hopefully make the measurements more precise than the
    existing methods of using RDTSC.

            Differential Revision: https://reviews.llvm.org/D77422