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Revision tags: llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4, llvmorg-18.1.3, llvmorg-18.1.2, llvmorg-18.1.1, llvmorg-18.1.0, llvmorg-18.1.0-rc4, llvmorg-18.1.0-rc3, llvmorg-18.1.0-rc2, llvmorg-18.1.0-rc1, llvmorg-19-init, llvmorg-17.0.6, llvmorg-17.0.5, llvmorg-17.0.4 |
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e3cf80c5 |
| 25-Oct-2023 |
Matthias Braun <matze@braunis.de> |
BlockFrequencyInfoImpl: Avoid big numbers, increase precision for small spreads
BlockFrequencyInfo calculates block frequencies as Scaled64 numbers but as a last step converts them to unsigned 64bit
BlockFrequencyInfoImpl: Avoid big numbers, increase precision for small spreads
BlockFrequencyInfo calculates block frequencies as Scaled64 numbers but as a last step converts them to unsigned 64bit integers (`BlockFrequency`). This improves the factors picked for this conversion so that:
* Avoid big numbers close to UINT64_MAX to avoid users overflowing/saturating when adding multiply frequencies together or when multiplying with integers. This leaves the topmost 10 bits unused to allow for some room.
* Spread the difference between hottest/coldest block as much as possible to increase precision.
* If the hot/cold spread cannot be represented loose precision at the lower end, but keep the frequencies at the upper end for hot blocks differentiable.
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Revision tags: llvmorg-17.0.3, llvmorg-17.0.2, llvmorg-17.0.1, llvmorg-17.0.0, llvmorg-17.0.0-rc4, llvmorg-17.0.0-rc3, llvmorg-17.0.0-rc2, llvmorg-17.0.0-rc1, llvmorg-18-init, llvmorg-16.0.6, llvmorg-16.0.5, llvmorg-16.0.4, llvmorg-16.0.3, llvmorg-16.0.2, llvmorg-16.0.1, llvmorg-16.0.0, llvmorg-16.0.0-rc4, llvmorg-16.0.0-rc3, llvmorg-16.0.0-rc2, llvmorg-16.0.0-rc1, llvmorg-17-init, llvmorg-15.0.7, llvmorg-15.0.6, llvmorg-15.0.5, llvmorg-15.0.4, llvmorg-15.0.3, working, llvmorg-15.0.2, llvmorg-15.0.1, llvmorg-15.0.0, llvmorg-15.0.0-rc3, llvmorg-15.0.0-rc2, llvmorg-15.0.0-rc1, llvmorg-16-init |
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0271ae65 |
| 18-Jul-2022 |
Fangrui Song <i@maskray.me> |
[test] Change test/SampleProfile to use opaque pointers
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Revision tags: llvmorg-14.0.6, llvmorg-14.0.5, llvmorg-14.0.4, llvmorg-14.0.3, llvmorg-14.0.2, llvmorg-14.0.1 |
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7a316c0a |
| 24-Mar-2022 |
Hongtao Yu <hoy@fb.com> |
[CSSPGO] Turn on profi and ext-tsp when using probe-based profile.
Probe-based profile leads to a better performance when combined with profi and ext-tsp block layout. I'm turning them on by default
[CSSPGO] Turn on profi and ext-tsp when using probe-based profile.
Probe-based profile leads to a better performance when combined with profi and ext-tsp block layout. I'm turning them on by default.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D122442
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Revision tags: llvmorg-14.0.0, llvmorg-14.0.0-rc4, llvmorg-14.0.0-rc3, llvmorg-14.0.0-rc2, llvmorg-14.0.0-rc1, llvmorg-15-init, llvmorg-13.0.1, llvmorg-13.0.1-rc3, llvmorg-13.0.1-rc2, llvmorg-13.0.1-rc1, llvmorg-13.0.0, llvmorg-13.0.0-rc4, llvmorg-13.0.0-rc3 |
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37e6a27d |
| 04-Sep-2021 |
Arthur Eubanks <aeubanks@google.com> |
[test] Fixup tests with -analyze in llvm/test/Transforms
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Revision tags: llvmorg-13.0.0-rc2, llvmorg-13.0.0-rc1, llvmorg-14-init, llvmorg-12.0.1, llvmorg-12.0.1-rc4, llvmorg-12.0.1-rc3, llvmorg-12.0.1-rc2 |
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0a0800c4 |
| 12-Jun-2021 |
spupyrev <spupyrev@fb.com> |
A post-processing for BFI inference
The current implementation for computing relative block frequencies does not handle correctly control-flow graphs containing irreducible loops. This results in su
A post-processing for BFI inference
The current implementation for computing relative block frequencies does not handle correctly control-flow graphs containing irreducible loops. This results in suboptimally generated binaries, whose perf can be up to 5% worse than optimal.
To resolve the problem, we apply a post-processing step, which iteratively updates block frequencies based on the frequencies of their predesessors. This corresponds to finding the stationary point of the Markov chain by an iterative method aka "PageRank computation". The algorithm takes at most O(|E| * IterativeBFIMaxIterations) steps but typically converges faster.
It is turned on by passing option `use-iterative-bfi-inference` and applied only for functions containing profile data and irreducible loops.
Tested on SPEC06/17, where it is helping to get correct profile counts for one of the binaries (403.gcc). In prod binaries, we've seen a speedup of up to 2%-5% for binaries containing functions with hot irreducible loops.
Reviewed By: hoy, wenlei, davidxl
Differential Revision: https://reviews.llvm.org/D103289
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