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Add CPU_FLAGS_* for amd64, arm, arm64, ppc64 and x86 to explicitly control minimal CPU intrinsic use. According to upstream, this should grant some performance benefit compared to the default use of dynamic dispatching based on CPU detection at runtime. Since upstream is heavily chaining flags one upon another, we respect upstream chains by stopping when a dependent flag is missing. Presumably, this should be less confusing than implicitly enabling it, and more user friendly than REQUIRED_USE. Also add USE=cpudetection to make it possible to disable dynamic dispatch for CPUs with more instruction sets. This should especially be useful when we are deliberately disabling some instruction sets to test NumPy without them. Signed-off-by: Michał Górny <mgorny@gentoo.org> Part-of: https://github.com/gentoo/gentoo/pull/43190 Closes: https://github.com/gentoo/gentoo/pull/43190 Signed-off-by: Michał Górny <mgorny@gentoo.org>
73 lines
3.0 KiB
Diff
73 lines
3.0 KiB
Diff
From 5591f1109b45a482bdaea3d3e44a80212a188edd Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny@quansight.com>
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Date: Mon, 28 Jul 2025 21:33:18 +0200
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Subject: [PATCH 1/2] BLD: provide explicit control over cpu-baseline detection
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Add a new `cpu-baseline-detect` feature flag that can be used to more
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precisely control the use of CPU baseline detection. This can be used
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by packages to more precisely control used SIMD code independently
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of compiler flags specified. The option follows typical feature
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semantics -- with `auto` preserving the current behavior of enabling
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when relevant compiler flags are found, `enabled` forcing it on
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based on the implicit compiler defaults, and `disabled` forcing it off.
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Signed-off-by: Michał Górny <mgorny@quansight.com>
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---
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meson.options | 2 ++
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meson_cpu/meson.build | 22 ++++++++++++----------
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2 files changed, 14 insertions(+), 10 deletions(-)
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diff --git a/meson.options b/meson.options
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index b09992fe9b91..f17f9901664a 100644
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--- a/meson.options
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+++ b/meson.options
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@@ -28,6 +28,8 @@ option('disable-optimization', type: 'boolean', value: false,
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description: 'Disable CPU optimized code (dispatch,simd,unroll...)')
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option('cpu-baseline', type: 'string', value: 'min',
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description: 'Minimal set of required CPU features')
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+option('cpu-baseline-detect', type: 'feature', value: 'auto',
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+ description: 'Detect CPU baseline from the compiler flags')
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option('cpu-dispatch', type: 'string', value: 'max -xop -fma4',
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description: 'Dispatched set of additional CPU features')
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option('test-simd', type: 'array',
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diff --git a/meson_cpu/meson.build b/meson_cpu/meson.build
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index e5b6d0fbe7be..1c4c6eecb308 100644
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--- a/meson_cpu/meson.build
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+++ b/meson_cpu/meson.build
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@@ -46,20 +46,22 @@ if get_option('disable-optimization')
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CPU_CONF_BASELINE = 'none'
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CPU_CONF_DISPATCH = 'none'
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else
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- baseline_detect = false
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+ baseline_detect = get_option('cpu-baseline-detect').enabled()
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c_args = get_option('c_args')
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- foreach arg : c_args
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- foreach carch : ['-march', '-mcpu', '-xhost', '/QxHost']
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- if arg.contains(carch)
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- message('Appending option "detect" to "cpu-baseline" due to detecting global architecture c_arg "' + arg + '"')
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- baseline_detect = true
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+ if get_option('cpu-baseline-detect').auto()
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+ foreach arg : c_args
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+ foreach carch : ['-march', '-mcpu', '-xhost', '/QxHost']
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+ if arg.contains(carch)
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+ message('Appending option "detect" to "cpu-baseline" due to detecting global architecture c_arg "' + arg + '"')
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+ baseline_detect = true
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+ break
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+ endif
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+ endforeach
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+ if baseline_detect
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break
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endif
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endforeach
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- if baseline_detect
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- break
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- endif
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- endforeach
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+ endif
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# The required minimal set of required CPU features.
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CPU_CONF_BASELINE = get_option('cpu-baseline')
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if baseline_detect
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