mirror of
https://github.com/mollyim/webrtc.git
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9ccbe17abb
This reverts commit ad148272b8.
Reason for revert: Causing test failures downstream.
Original change's description:
> Activating AVX2 support by default
>
> This CL activates the newly added AVX2 support by default.
> The activation is done beneath a kill-switch.
>
> Beyond the above, the CL also changes an incorrect DCHECK_GT
> to a DCHECK_GE.
>
> Bug: webrtc:11663
> Change-Id: I231ccb2f5efabf74cd8190411daa954b2b94a2a0
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/183042
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Reviewed-by: Sam Zackrisson <saza@webrtc.org>
> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32193}
TBR=mbonadei@webrtc.org,saza@webrtc.org,peah@webrtc.org,kwiberg@webrtc.org
Change-Id: If2287a0a4b37931ce5f85baae093a66b19d0a78b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:11663
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185481
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32196}
113 lines
3.3 KiB
C++
113 lines
3.3 KiB
C++
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// Parts of this file derived from Chromium's base/cpu.cc.
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#include "rtc_base/system/arch.h"
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#include "system_wrappers/include/cpu_features_wrapper.h"
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#if defined(WEBRTC_ARCH_X86_FAMILY) && defined(_MSC_VER)
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#include <intrin.h>
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#endif
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namespace webrtc {
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// No CPU feature is available => straight C path.
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int GetCPUInfoNoASM(CPUFeature feature) {
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(void)feature;
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return 0;
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}
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#if defined(WEBRTC_ARCH_X86_FAMILY)
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#if defined(WEBRTC_ENABLE_AVX2)
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// xgetbv returns the value of an Intel Extended Control Register (XCR).
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// Currently only XCR0 is defined by Intel so |xcr| should always be zero.
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static uint64_t xgetbv(uint32_t xcr) {
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#if defined(_MSC_VER)
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return _xgetbv(xcr);
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#else
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uint32_t eax, edx;
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__asm__ volatile("xgetbv" : "=a"(eax), "=d"(edx) : "c"(xcr));
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return (static_cast<uint64_t>(edx) << 32) | eax;
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#endif // _MSC_VER
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}
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#endif // WEBRTC_ENABLE_AVX2
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#ifndef _MSC_VER
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// Intrinsic for "cpuid".
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#if defined(__pic__) && defined(__i386__)
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static inline void __cpuid(int cpu_info[4], int info_type) {
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__asm__ volatile(
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"mov %%ebx, %%edi\n"
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"cpuid\n"
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"xchg %%edi, %%ebx\n"
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: "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]),
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"=d"(cpu_info[3])
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: "a"(info_type));
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}
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#else
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static inline void __cpuid(int cpu_info[4], int info_type) {
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__asm__ volatile("cpuid\n"
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: "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
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"=d"(cpu_info[3])
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: "a"(info_type), "c"(0));
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}
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#endif
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#endif // _MSC_VER
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#endif // WEBRTC_ARCH_X86_FAMILY
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#if defined(WEBRTC_ARCH_X86_FAMILY)
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// Actual feature detection for x86.
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int GetCPUInfo(CPUFeature feature) {
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int cpu_info[4];
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__cpuid(cpu_info, 1);
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if (feature == kSSE2) {
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return 0 != (cpu_info[3] & 0x04000000);
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}
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if (feature == kSSE3) {
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return 0 != (cpu_info[2] & 0x00000001);
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}
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#if defined(WEBRTC_ENABLE_AVX2)
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if (feature == kAVX2) {
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int cpu_info7[4];
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__cpuid(cpu_info7, 0);
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int num_ids = cpu_info7[0];
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if (num_ids < 7) {
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return 0;
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}
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// Interpret CPU feature information.
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__cpuid(cpu_info7, 7);
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// AVX instructions can be used when
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// a) AVX are supported by the CPU,
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// b) XSAVE is supported by the CPU,
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// c) XSAVE is enabled by the kernel.
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// See http://software.intel.com/en-us/blogs/2011/04/14/is-avx-enabled
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// AVX2 support needs (avx_support && (cpu_info7[1] & 0x00000020) != 0;).
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return (cpu_info[2] & 0x10000000) != 0 &&
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(cpu_info[2] & 0x04000000) != 0 /* XSAVE */ &&
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(cpu_info[2] & 0x08000000) != 0 /* OSXSAVE */ &&
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(xgetbv(0) & 0x00000006) == 6 /* XSAVE enabled by kernel */ &&
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(cpu_info7[1] & 0x00000020) != 0;
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}
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#endif // WEBRTC_ENABLE_AVX2
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return 0;
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}
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#else
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// Default to straight C for other platforms.
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int GetCPUInfo(CPUFeature feature) {
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(void)feature;
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return 0;
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}
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#endif
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} // namespace webrtc
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