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cputime optimize for arm64 - #3247

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chenBright merged 4 commits into
apache:masterfrom
dwh110:cputime_opt
Aug 6, 2026
Merged

cputime optimize for arm64#3247
chenBright merged 4 commits into
apache:masterfrom
dwh110:cputime_opt

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@dwh110

@dwh110 dwh110 commented Mar 23, 2026

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What problem does this PR solve?

Issue Number: n/a

Problem Summary: cpugettime optimize for ARM64

What is changed and the side effects?

Changed:
detail::invariant_cpu_freq value get by CNTFRQ_EL0

Side effects:

  • Performance effects:

  • Breaking backward compatibility: 无

Check List:

@wwbmmm
wwbmmm requested a review from Copilot March 24, 2026 02:44
Copilot AI reviewed Mar 24, 2026
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Pull request overview

This PR aims to optimize cpuwide_time_ns() on ARM64 by using the architectural counter frequency (CNTFRQ_EL0) to populate detail::invariant_cpu_freq, shifting initialization away from per-call logic.

Changes:

  • On __aarch64__, route cpuwide_time_ns() to use the cycle-counter path instead of the clock_gettime path.
  • Move initialization of detail::invariant_cpu_freq into a pre-main initializer, using CNTFRQ_EL0 on ARM64.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File Description
src/butil/time.h Changes cpuwide_time_ns() preprocessor gating to include ARM64 in the invariant-counter fast path and removes lazy init recursion.
src/butil/time.cpp Adds a pre-main initializer to set detail::invariant_cpu_freq, reading CNTFRQ_EL0 on ARM64.

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Comment thread src/butil/time.h
Comment thread src/butil/time.cpp Outdated
Comment thread src/butil/time.cpp Outdated
Comment thread src/butil/time.cpp Outdated
wasphin
wasphin reviewed Jul 15, 2026
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Comment thread src/butil/time.h Outdated
Comment thread src/butil/time.cpp Outdated
@dwh110
dwh110 marked this pull request as draft July 18, 2026 07:37
@dwh110
dwh110 marked this pull request as ready for review July 18, 2026 07:37
@dwh110
dwh110 force-pushed the cputime_opt branch 2 times, most recently from 3f81407 to 3cff1a7 Compare July 20, 2026 13:56
@dwh110

dwh110 commented Jul 20, 2026 •
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@wwbmmm @wasphin Could you help take a look at how to resolve this?
image

@dwh110 dwh110 closed this Jul 20, 2026
@dwh110 dwh110 reopened this Jul 20, 2026
@dwh110

dwh110 commented Jul 21, 2026

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@wwbmmm @wasphin please check it, looking forward to merging it into the main branch.

@wwbmmm

wwbmmm commented Jul 26, 2026

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LGTM

chenBright
chenBright approved these changes Jul 26, 2026
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Comment thread src/butil/time.h Outdated
@dwh110
dwh110 force-pushed the cputime_opt branch 2 times, most recently from 7d1d9e0 to 869c04a Compare July 31, 2026 01:08
chenBright
chenBright requested changes Jul 31, 2026
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The build script needs to support enabling BUTIL_USE_CPU_FREQUENCY, see BRPC_WITH_GLOG.

@dwh110

dwh110 commented Aug 5, 2026

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The build script needs to support enabling BUTIL_USE_CPU_FREQUENCY, see BRPC_WITH_GLOG.

@chenBright OK，Referenced BRPC_WITH_GLOG for the following adaptations：
1、Activation options: CMake -DWITH_CPU_FREQUENCY=ON, Bazel --define BUTIL_USE_CPU_FREQUENCY=true, script argument --with-cpu-frequency.
2、Disabled by default for consistent legacy behavior.

dwh110 and others added 2 commits August 5, 2026 20:10
@dwh110 seekdwh
cputime optimize for arm64
03a5cc4 
Update src/butil/time.cpp
modify  using __attribute__((constructor)) and merge init_invariant_cpu_freq to inside function read_invariant_cpu_frequency
seekdwh
Add the macro switch BUTIL_USE_CPU_FREQUENCY while preserving the ori…
e705415 
…ginal default behavior for ARM64
seekdwh
1、Activation options: CMake -DWITH_CPU_FREQUENCY=ON, Bazel --define B…
9538fdf 
…UTIL_USE_CPU_FREQUENCY=true, script argument --with-cpu-frequency.

2、Disabled by default for consistent legacy behavior.
@dwh110

dwh110 commented Aug 6, 2026

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@chenBright pls review again，tks

@wasphin

wasphin commented Aug 6, 2026

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LGTM

chenBright
chenBright approved these changes Aug 6, 2026
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LGTM

@chenBright
chenBright merged commit 956227b into apache:master Aug 6, 2026
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