[BOLT] Compress YAML pseudo probe information#166680
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You can test this locally with the following command:git-clang-format --diff origin/main HEAD --extensions cpp,h -- bolt/include/bolt/Profile/ProfileYAMLMapping.h bolt/include/bolt/Profile/YAMLProfileWriter.h bolt/include/bolt/Utils/CommandLineOpts.h bolt/lib/Profile/DataAggregator.cpp bolt/lib/Profile/YAMLProfileReader.cpp bolt/lib/Profile/YAMLProfileWriter.cpp bolt/lib/Rewrite/PseudoProbeRewriter.cpp --diff_from_common_commit
View the diff from clang-format here.diff --git a/bolt/lib/Profile/YAMLProfileWriter.cpp b/bolt/lib/Profile/YAMLProfileWriter.cpp
index aad433a8b..817590cb9 100644
--- a/bolt/lib/Profile/YAMLProfileWriter.cpp
+++ b/bolt/lib/Profile/YAMLProfileWriter.cpp
@@ -485,7 +485,7 @@ std::error_code YAMLProfileWriter::writeProfile(const RewriteInstance &RI) {
// Add probe inline tree nodes.
InlineTreeDesc InlineTree;
if (const MCPseudoProbeDecoder *Decoder =
- opts::ProfileWritePseudoProbes ? BC.getPseudoProbeDecoder() : nullptr)
+ opts::ProfileWritePseudoProbes ? BC.getPseudoProbeDecoder() : nullptr)
std::tie(BP.PseudoProbeDesc, InlineTree) = convertPseudoProbeDesc(*Decoder);
// Add all function objects.
|
aaupov
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Nov 6, 2025
Pseudo probe matching (#100446) needs callee information for call probes. Embed call probe information (probe id, inline tree node, indirect flag) into CallSiteInfo. As a consequence: - Remove call probes from PseudoProbeInfo to avoid duplication, making it only contain block probes. - Probe grouping across inline tree nodes becomes more potent + allows to unambiguously elide block id 1 (common case). Block mask (blx) encoding becomes a low-ROI optimization and will be replaced by a more compact encoding leveraging simplified PseudoProbeInfo in #166680. The size increase is ~3% for an XL profile (461->475MB). Compact block probe encoding shrinks it by ~6%. Test Plan: updated pseudoprobe-decoding-{inline,noinline}.test
aaupov
added a commit
that referenced
this pull request
Nov 11, 2025
Pseudo probe matching (#100446) needs callee information for call probes. Embed call probe information (probe id, inline tree node, indirect flag) into CallSiteInfo. As a consequence: - Remove call probes from PseudoProbeInfo to avoid duplication, making it only contain block probes. - Probe grouping across inline tree nodes becomes more potent + allows to unambiguously elide block id 1 (common case). Block mask (blx) encoding becomes a low-ROI optimization and will be replaced by a more compact encoding leveraging simplified PseudoProbeInfo in #166680. The size increase is ~3% for an XL profile (461->475MB). Compact block probe encoding shrinks it by ~6%. Test Plan: updated pseudoprobe-decoding-{inline,noinline}.test Reviewers: paschalis-mpeis, ayermolo, yota9, yozhu, rafaelauler, maksfb Reviewed By: rafaelauler Pull Request: #165490
🐧 Linux x64 Test ResultsThe build failed before running any tests. Click on a failure below to see the details. tools/bolt/lib/Profile/CMakeFiles/LLVMBOLTProfile.dir/YAMLProfileReader.cpp.oIf these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the |
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Introduce an optional value
compactforprofile-write-pseudo-probesflag,enabling compressed encoding of pseudo probe information in YAML profile:
inline tree nodes in format
[probes]_[nodes]:[from,...,to]are coalesced intofrom^run_length,using base36-encoding.
This significantly reduces the size of YAML profile and makes parsing faster
(as it replaces nested FlowVectors with strings).
Test Plan:
TBD: compress pseudo_probe_desc. Use DFS for probes, and BFS for inline tree.
Measure emission time.