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author | Stefano Brivio <sbrivio@redhat.com> | 2022-02-28 16:18:44 +0100 |
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committer | Stefano Brivio <sbrivio@redhat.com> | 2022-02-28 16:46:28 +0100 |
commit | 213c397492bdc64cf26b2e7b3877e4a29dc9f8da (patch) | |
tree | 50f69783c009918e6a1ef5a22b2d7d88407488e2 /arch.c | |
parent | deca1ebe5093affd581a27855180821a8b6b3079 (diff) | |
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passt, pasta: Run-time selection of AVX2 build
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>
Diffstat (limited to 'arch.c')
-rw-r--r-- | arch.c | 42 |
1 files changed, 42 insertions, 0 deletions
@@ -0,0 +1,42 @@ +// SPDX-License-Identifier: AGPL-3.0-or-later + +/* PASST - Plug A Simple Socket Transport + * for qemu/UNIX domain socket mode + * + * PASTA - Pack A Subtle Tap Abstraction + * for network namespace/tap device mode + * + * arch.c - Architecture-specific implementations + * + * Copyright (c) 2022 Red Hat GmbH + * Author: Stefano Brivio <sbrivio@redhat.com> + */ + +#include <limits.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +/** + * arch_avx2_exec() - Run AVX2 build if supported, drop suffix from argv[0] + * @argv: Arguments from command line + */ +#ifdef __x86_64__ +void arch_avx2_exec(char **argv) +{ + char *p = strstr(argv[0], ".avx2"); + + if (p) { + *p = 0; + } else if (__builtin_cpu_supports("avx2")) { + char path[PATH_MAX]; + + snprintf(path, PATH_MAX, "%s.avx2", argv[0]); + argv[0] = path; + execve(path, argv, environ); + perror("Can't run AVX2 build, using non-AVX2 version"); + } +} +#else +void arch_avx2_exec(char **argv) { (void)argv; } +#endif |