bazel: Enable LTO only in PGO build#29514
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StephanDollberg merged 1 commit intodevfrom Feb 4, 2026
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Pull request overview
This PR optimizes Redpanda's build configuration by enabling Link Time Optimization (LTO) exclusively for Profile-Guided Optimization (PGO) builds, rather than for all release builds. This change improves build times for standard release builds while maintaining optimization for the primary PGO release builds.
Changes:
- Moved LTO flags from general release configuration to PGO-specific configuration
- Removed
-ffat-lto-objectsflag as it's no longer needed - Introduced new
pgo-baseconfiguration to consolidate PGO-specific LTO settings
PGO is the main release build so enable LTO only then. Saves some time in the basic release build. Also disable fat lto objects. There is no point in using them anymore as the PGO build isn't shared with anything anyway. This speeds up both the non-PGO and PGO build and also reduces object sizes.
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travisdowns
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Feb 4, 2026
| # bazel seems to pass -fprofile-correction unconditionally but that only exists | ||
| # in gcc so need to make clang ignore it | ||
| build:pgo-optimize --copt -Wno-ignored-optimization-argument | ||
| build:pgo-optimize --config=pgo-base --copt -Wno-ignored-optimization-argument |
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details on ignored-optimization-arg?
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sorry I didn't notice it wasn't added in this change
travisdowns
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Feb 4, 2026
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PGO is the main release build so enable LTO only then. Saves some time
in the basic release build.
Also disable fat lto objects. There is no point in using them anymore as
the PGO build isn't shared with anything anyway.
This speeds up both the non-PGO and PGO build and also reduces object
sizes.
Backports Required
Release Notes