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Build-time selection of AVX2 flags and routines is not practical for distributions, but limiting AVX2 usage to checksum routines with specific run-time detection doesn't allow for easy performance gains from auto-vectorisation of batched packet handling routines. For x86_64, build non-AVX2 and AVX2 binaries, and implement a simple wrapper replacing the current executable with the AVX2 build if it's available, and if AVX2 is supported by the current CPU. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
43 lines
960 B
C
43 lines
960 B
C
// SPDX-License-Identifier: AGPL-3.0-or-later
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/* PASST - Plug A Simple Socket Transport
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* for qemu/UNIX domain socket mode
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*
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* PASTA - Pack A Subtle Tap Abstraction
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* for network namespace/tap device mode
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*
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* arch.c - Architecture-specific implementations
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*
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* Copyright (c) 2022 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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/**
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* arch_avx2_exec() - Run AVX2 build if supported, drop suffix from argv[0]
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* @argv: Arguments from command line
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*/
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#ifdef __x86_64__
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void arch_avx2_exec(char **argv)
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{
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char *p = strstr(argv[0], ".avx2");
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if (p) {
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*p = 0;
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} else if (__builtin_cpu_supports("avx2")) {
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char path[PATH_MAX];
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snprintf(path, PATH_MAX, "%s.avx2", argv[0]);
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argv[0] = path;
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execve(path, argv, environ);
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perror("Can't run AVX2 build, using non-AVX2 version");
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}
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}
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#else
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void arch_avx2_exec(char **argv) { (void)argv; }
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#endif
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