Re: [PATCH v3 09/11] net: simplify build-time logic for x86

[David Marchand <david.marchand@redhat.com>]

On Tue, Mar 18, 2025 at 6:36 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> All DPDK-supported versions of clang and gcc have the "-mpclmul" and
> "-maes" flags, so we never need to check for those. This allows the SSE
> code path to be unconditionally built on x86.
>
> For the AVX512 code path, simplify it by only checking for the
> build-time support, and always doing a separate build with AVX512
> support when that compiler support is present.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  lib/net/meson.build   | 53 +++++--------------------------------------
>  lib/net/rte_net_crc.c |  8 +++----
>  2 files changed, 10 insertions(+), 51 deletions(-)
>
> diff --git a/lib/net/meson.build b/lib/net/meson.build
> index c9b34afc98..4bbbad3f42 100644
> --- a/lib/net/meson.build
> +++ b/lib/net/meson.build
> @@ -42,57 +42,16 @@ deps += ['mbuf']
>  use_function_versioning = true
>
>  if dpdk_conf.has('RTE_ARCH_X86_64')
> -    net_crc_sse42_cpu_support = (cc.get_define('__PCLMUL__', args: machine_args) != '')
> -    net_crc_avx512_cpu_support = (
> -            target_has_avx512 and
> -            cc.get_define('__VPCLMULQDQ__', args: machine_args) != ''
> -    )
> -
> -    net_crc_sse42_cc_support = (cc.has_argument('-mpclmul') and cc.has_argument('-maes'))
> -    net_crc_avx512_cc_support = (cc.has_argument('-mvpclmulqdq') and cc_has_avx512)
> -
> -    build_static_net_crc_sse42_lib = 0
> -    build_static_net_crc_avx512_lib = 0
> -
> -    if net_crc_sse42_cpu_support == true
> -        sources += files('net_crc_sse.c')
> -        cflags += ['-DCC_X86_64_SSE42_PCLMULQDQ_SUPPORT']
> -        if net_crc_avx512_cpu_support == true
> -            sources += files('net_crc_avx512.c')
> -            cflags += ['-DCC_X86_64_AVX512_VPCLMULQDQ_SUPPORT']
> -        elif net_crc_avx512_cc_support == true
> -            build_static_net_crc_avx512_lib = 1
> -            net_crc_avx512_lib_cflags = cc_avx512_flags + ['-mvpclmulqdq']
> -            cflags += ['-DCC_X86_64_AVX512_VPCLMULQDQ_SUPPORT']
> -        endif
> -    elif net_crc_sse42_cc_support == true
> -        build_static_net_crc_sse42_lib = 1
> -        net_crc_sse42_lib_cflags = ['-mpclmul', '-maes']
> -        cflags += ['-DCC_X86_64_SSE42_PCLMULQDQ_SUPPORT']
> -        if net_crc_avx512_cc_support == true
> -            build_static_net_crc_avx512_lib = 1
> -            net_crc_avx512_lib_cflags = cc_avx512_flags + ['-mvpclmulqdq', '-mpclmul']
> -            cflags += ['-DCC_X86_64_AVX512_VPCLMULQDQ_SUPPORT']
> -        endif
> -    endif
> -
> -    if build_static_net_crc_sse42_lib == 1
> -        net_crc_sse42_lib = static_library(
> -                'net_crc_sse42_lib',
> -                'net_crc_sse.c',
> -                dependencies: static_rte_eal,
> -                c_args: [cflags,
> -                    net_crc_sse42_lib_cflags])
> -        objs += net_crc_sse42_lib.extract_objects('net_crc_sse.c')
> -    endif
> -
> -    if build_static_net_crc_avx512_lib == 1
> +    sources += files('net_crc_sse.c')
> +    cflags += ['-mpclmul', '-maes']
> +    if cc.has_argument('-mvpclmulqdq') and cc_has_avx512
> +        net_crc_avx512_lib_cflags = cc_avx512_flags + ['-mvpclmulqdq']

Nit: we don't need this intermediate variable. But well, it gets
removed in next patch.

> +        cflags += ['-DCC_X86_64_AVX512_VPCLMULQDQ_SUPPORT']
>          net_crc_avx512_lib = static_library(
>                  'net_crc_avx512_lib',
>                  'net_crc_avx512.c',
>                  dependencies: static_rte_eal,
> -                c_args: [cflags,
> -                    net_crc_avx512_lib_cflags])
> +                c_args: [cflags, net_crc_avx512_lib_cflags])
>          objs += net_crc_avx512_lib.extract_objects('net_crc_avx512.c')
>      endif
>
> diff --git a/lib/net/rte_net_crc.c b/lib/net/rte_net_crc.c
> index 2fb3eec231..c9773d6300 100644
> --- a/lib/net/rte_net_crc.c
> +++ b/lib/net/rte_net_crc.c
> @@ -66,7 +66,7 @@ static const rte_net_crc_handler handlers_avx512[] = {
>         [RTE_NET_CRC32_ETH] = rte_crc32_eth_avx512_handler,
>  };
>  #endif
> -#ifdef CC_X86_64_SSE42_PCLMULQDQ_SUPPORT
> +#ifdef RTE_ARCH_X86_64
>  static const rte_net_crc_handler handlers_sse42[] = {
>         [RTE_NET_CRC16_CCITT] = rte_crc16_ccitt_sse42_handler,
>         [RTE_NET_CRC32_ETH] = rte_crc32_eth_sse42_handler,
> @@ -211,7 +211,7 @@ avx512_vpclmulqdq_init(void)
>  static const rte_net_crc_handler *
>  sse42_pclmulqdq_get_handlers(void)
>  {
> -#ifdef CC_X86_64_SSE42_PCLMULQDQ_SUPPORT
> +#ifdef RTE_ARCH_X86_64
>         if (SSE42_PCLMULQDQ_CPU_SUPPORTED &&
>                         max_simd_bitwidth >= RTE_VECT_SIMD_128)
>                 return handlers_sse42;
> @@ -223,7 +223,7 @@ sse42_pclmulqdq_get_handlers(void)
>  static void
>  sse42_pclmulqdq_init(void)
>  {
> -#ifdef CC_X86_64_SSE42_PCLMULQDQ_SUPPORT
> +#ifdef RTE_ARCH_x86_64
>         if (SSE42_PCLMULQDQ_CPU_SUPPORTED)
>                 rte_net_crc_sse42_init();
>  #endif
> @@ -316,7 +316,7 @@ handlers_init(enum rte_net_crc_alg alg)
>  #endif
>                 /* fall-through */
>         case RTE_NET_CRC_SSE42:
> -#ifdef CC_X86_64_SSE42_PCLMULQDQ_SUPPORT
> +#ifdef RTE_ARCH_X86_64
>                 if (SSE42_PCLMULQDQ_CPU_SUPPORTED) {
>                         handlers_dpdk26[alg].f[RTE_NET_CRC16_CCITT] =
>                                 rte_crc16_ccitt_sse42_handler;
> --
> 2.43.0
>

-- 
David Marchand