[all-commits] [llvm/llvm-project] 8c2c97: [CSSPGO][llvm-profgen] Ignore LBR records after in...

[Hongtao Yu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8c2c97287eacda1ed9cbee893054d868e3b990c5
      https://github.com/llvm/llvm-project/commit/8c2c97287eacda1ed9cbee893054d868e3b990c5
  Author: Hongtao Yu <hoy at fb.com>
  Date:   2021-06-18 (Fri, 18 Jun 2021)

  Changed paths:
    A llvm/test/tools/llvm-profgen/Inputs/cs-interrupt.perfscript
    A llvm/test/tools/llvm-profgen/cs-interrupt.test
    M llvm/tools/llvm-profgen/PerfReader.cpp

  Log Message:
  -----------
  [CSSPGO][llvm-profgen] Ignore LBR records after interrupt transition

If we have seen an inwards transition from external code to internal code, but not a following outwards transition, the inwards transition is likely due to interrupt which is usually unpaired. Ignore current  and subsequent entries since they are likely from an unrelated pre-interrupt context.

LBR records from different interrupt context are unrelated and they should not be mixed together. Currenlty the OS does this for task-scheduling interrupt but not for all interrupts.

Reviewed By: wenlei, wlei

Differential Revision: https://reviews.llvm.org/D104276