[all-commits] [llvm/llvm-project] 614b8b: [libFuzzer] Deflake entropic exec-time test.

[Dokyung Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 614b8bac01f6e9b877bd9a3a379c3bb8074f1f4a
      https://github.com/llvm/llvm-project/commit/614b8bac01f6e9b877bd9a3a379c3bb8074f1f4a
  Author: Dokyung Song <dokyung.song at gmail.com>
  Date:   2021-11-10 (Wed, 10 Nov 2021)

  Changed paths:
    M compiler-rt/test/fuzzer/EntropicScalePerExecTimeTest.cpp

  Log Message:
  -----------
  [libFuzzer] Deflake entropic exec-time test.

Entropic scheduling with exec-time option can be misled, if inputs
on the right path to become crashing inputs accidentally take more
time to execute before it's added to the corpus. This patch, by letting
more of such inputs added to the corpus (four inputs of size 7 to 10,
instead of a single input of size 2), reduces possibilities of being
influenced by timing flakiness.

A longer-term fix could be to reduce timing flakiness in the fuzzer;
one way could be to execute inputs multiple times and take average of
their execution time before they are added to the corpus.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D113544