wmi added inline comments.
================
Comment at: llvm/include/llvm/IR/PseudoProbe.h:41
// [18:3] - probe id
- // [25:19] - reserved
+ // [25:19] - probe distribution factor
// [28:26] - probe type, see PseudoProbeType
----------------
The bits in discriminator is a scare resource. Have you considered using less
bits to represent probe distribution factor? I guess it is possible that using
a little more coarse grain distribution factor won't affect performance.
================
Comment at: llvm/include/llvm/Passes/StandardInstrumentations.h:273
IRChangedPrinter PrintChangedIR;
+ PseudoProbeVerifier PseudoProbeVerification;
VerifyInstrumentation Verify;
----------------
Before PseudoProbeUpdate pass, there is no need to verify because
PseudoProbeUpdate will make distribution factor consistent. PseudoProbeUpdate
run in a late stage in the lto/thinlto prelink pipeline, and no many passes
need the verification, so what is the major usage of PseudoProbeVerifier?
================
Comment at: llvm/lib/Transforms/IPO/SampleProfileProbe.cpp:133-134
+ float PrevProbeFactor = PrevProbeFactors[I.first];
+ if (std::abs(CurProbeFactor - PrevProbeFactor) >
+ DistributionFactorVariance) {
+ if (!BannerPrinted) {
----------------
Why not issue warning/error message when verification fails? That will make
enabling the verification in release compiler possible.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D93264/new/
https://reviews.llvm.org/D93264
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
