[all-commits] [llvm/llvm-project] 233ca8: [exegesis] Benchmark: provide optional progress me...

[Roman Lebedev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 233ca84a25a7ba14aac7bcbd1956d6f528d4395f
      https://github.com/llvm/llvm-project/commit/233ca84a25a7ba14aac7bcbd1956d6f528d4395f
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2022-12-13 (Tue, 13 Dec 2022)

  Changed paths:
    A llvm/tools/llvm-exegesis/lib/ProgressMeter.h
    M llvm/tools/llvm-exegesis/llvm-exegesis.cpp
    M llvm/unittests/tools/llvm-exegesis/CMakeLists.txt
    A llvm/unittests/tools/llvm-exegesis/ProgressMeterTest.cpp

  Log Message:
  -----------
  [exegesis] Benchmark: provide optional progress meter / ETA

Now that `--opcode-index=-1` is mostly stable,
and i can migrate off of my custom tooling that emulated it,
there comes a bit of confusion as to the status of the run.

It is normal for the single all-opcode run to take ~3 minutes,
and it's a bit more than one can be comfortable with,
without having some sort of visual indication of the progress.

Thus, i present:
```
$ ./bin/llvm-exegesis -mode=inverse_throughput --opcode-index=-1 --benchmarks-file=/dev/null --dump-object-to-disk=0 --measurements-print-progress --skip-measurements
<...>
XAM_Fp80: unsupported opcode: pseudo instruction
XBEGIN: Unsupported opcode: isPseudo/usesCustomInserter
XBEGIN_2: Unsupported opcode: isBranch/isIndirectBranch
XBEGIN_4: Unsupported opcode: isBranch/isIndirectBranch
XCH_F: unsupported second-form X87 instruction
Processing...   1%, ETA 02:10
Processing...   2%, ETA 02:03
Processing...   3%, ETA 02:00
Processing...   4%, ETA 01:57
Processing...   5%, ETA 01:54
Processing...   6%, ETA 01:53
Processing...   7%, ETA 01:51
Processing...   8%, ETA 01:50
Processing...   9%, ETA 01:49
Processing...  10%, ETA 01:48
Processing...  11%, ETA 01:46
Processing...  12%, ETA 01:45
Processing...  13%, ETA 01:44
Processing...  14%, ETA 01:43
Processing...  15%, ETA 01:42
Processing...  16%, ETA 01:42
Processing...  17%, ETA 01:41
```

As usual, the ETA estimation is statically-insignificant,
and is a lie/does not converge at least until 50% through.
It would be nice to have an actual progress indicator like in LIT,
but i'm not sure we have such a luxury in C++ form in LLVM codebase already.

Reviewed By: courbet

Differential Revision: https://reviews.llvm.org/D139797