Revision (<<< Hide revision tags) (Show revision tags >>>) Date Author Comments
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
# 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.

show more ...


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
# 0271ae65 18-Jul-2022 Fangrui Song <i@maskray.me>

[test] Change test/SampleProfile to use opaque pointers


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
# 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

show more ...


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
# 37e6a27d 04-Sep-2021 Arthur Eubanks <aeubanks@google.com>

[test] Fixup tests with -analyze in llvm/test/Transforms


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
# 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

show more ...