[PATCH] D60000: [llvm-exegesis] Post-processing for chained instrs in latency mode (PR41275)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri updated this revision to Diff 342824.
lebedev.ri changed the repository for this revision from rL LLVM to rG LLVM Github Monorepo.
lebedev.ri added a subscriber: fhahn.
lebedev.ri added a comment.
Herald added a subscriber: dexonsmith.

Now that i'm renewly motivated to finally get this fixed, let's try again :)

This implements linear algebra support library (i don't think we want to pull in eigen do we?),
implements ordinary/weighted least squares, and uses it to post-process latency benchmark points.

This kinda just works: F16665621: latency-clusters-ols.html <https://reviews.llvm.org/F16665621> vs F16422601: latency-clusters.html <https://reviews.llvm.org/F16422601>
But i've made two observations:

1. if we measured a single instruction, we can say that the measurement is precise, so it's estimator should deviate from the actual measurement by as little as possible => weighted least squares
2. i was really hoping i wouldn't have to deal with domain transfer delays, but the results are kinda bogus right now :) That, or there is some other issue.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60000/new/

https://reviews.llvm.org/D60000

Files:
  llvm/include/llvm/Support/LinearAlgebra.h
  llvm/test/tools/llvm-exegesis/X86/analysis-latency-instruction-chaining-domain-transfer.test
  llvm/test/tools/llvm-exegesis/X86/analysis-latency-instruction-chaining.test
  llvm/tools/llvm-exegesis/lib/Analysis.cpp
  llvm/tools/llvm-exegesis/lib/CMakeLists.txt
  llvm/tools/llvm-exegesis/lib/PostProcessing.cpp
  llvm/tools/llvm-exegesis/lib/PostProcessing.h
  llvm/tools/llvm-exegesis/llvm-exegesis.cpp
  llvm/unittests/Support/CMakeLists.txt
  llvm/unittests/Support/LinearAlgebraTest.cpp
  tools/llvm-exegesis/lib/PostProcessing.cpp
  tools/llvm-exegesis/lib/PostProcessing.h

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