From: David Marchand <david.marchand@redhat.com> To: dev@dpdk.org Cc: viktorin@rehivetech.com, ruifeng.wang@arm.com, jerinj@marvell.com, drc@linux.vnet.ibm.com, bruce.richardson@intel.com, konstantin.ananyev@intel.com, ciara.power@intel.com, Kevin Laatz <kevin.laatz@intel.com> Subject: [dpdk-dev] [PATCH v10 02/18] doc: describe how to enable AVX512 Date: Mon, 19 Oct 2020 15:48:42 +0200 Message-ID: <20201019134858.32507-3-david.marchand@redhat.com> (raw) In-Reply-To: <20201019134858.32507-1-david.marchand@redhat.com> From: Ciara Power <ciara.power@intel.com> This patch adds documentation on the usage of the max SIMD bitwidth EAL setting to enable AVX-512 at runtime. Signed-off-by: Ciara Power <ciara.power@intel.com> Acked-by: Kevin Laatz <kevin.laatz@intel.com> --- v6: Updated enum value. v4: Updated docs to reflect renamed enum. v3: - Added enum value for disabling use of max SIMD to doc. - Added entry to HowTo index. --- doc/guides/howto/avx512.rst | 36 ++++++++++++++++++++++++++++++++++++ doc/guides/howto/index.rst | 1 + 2 files changed, 37 insertions(+) create mode 100644 doc/guides/howto/avx512.rst diff --git a/doc/guides/howto/avx512.rst b/doc/guides/howto/avx512.rst new file mode 100644 index 0000000000..6c034b617d --- /dev/null +++ b/doc/guides/howto/avx512.rst @@ -0,0 +1,36 @@ +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2020 Intel Corporation. + + +Using AVX-512 with DPDK +======================= + +AVX-512 is not used by default in DPDK, but it can be selected at runtime by apps through the use of EAL API, +and by the user with a commandline argument. DPDK has a setting for max SIMD bitwidth, +which can be modified and will then limit the vector path taken by the code. + + +Using the API in apps +--------------------- + +Apps can request DPDK uses AVX-512 at runtime, if it provides improved application performance. +This can be done by modifying the EAL setting for max SIMD bitwidth to 512, as by default it is 256, +which does not allow for AVX-512. + +.. code-block:: c + + rte_vect_set_max_simd_bitwidth(RTE_VECT_SIMD_512); + +This API should only be called once at initialization, before EAL init. +For more information on the possible enum values to use as a parameter, go to :ref:`max_simd_bitwidth`: + + +Using the command-line argument +--------------------------------------------- + +The user can select to use AVX-512 at runtime, using the following argument to set the max bitwidth:: + + ./app/dpdk-testpmd --force-max-simd-bitwidth=512 + +This will override any further changes to the max SIMD bitwidth in DPDK, +which is useful for testing purposes. diff --git a/doc/guides/howto/index.rst b/doc/guides/howto/index.rst index 5a97ea508c..c2a2c60ddb 100644 --- a/doc/guides/howto/index.rst +++ b/doc/guides/howto/index.rst @@ -20,3 +20,4 @@ HowTo Guides telemetry debug_troubleshoot openwrt + avx512 -- 2.23.0
next prev parent reply other threads:[~2020-10-19 13:50 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-19 13:48 [dpdk-dev] [PATCH v10 00/18] add max SIMD bitwidth to EAL David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 01/18] eal: control max SIMD bitwidth David Marchand 2020-10-19 13:48 ` David Marchand [this message] 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 03/18] net/i40e: check " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 04/18] net/axgbe: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 05/18] net/bnxt: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 06/18] net/enic: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 07/18] net/fm10k: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 08/18] net/iavf: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 09/18] net/ice: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 10/18] net/ixgbe: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 11/18] net/mlx5: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 12/18] net/virtio: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 13/18] distributor: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 14/18] member: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 15/18] efd: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 16/18] net: " David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 17/18] node: choose vector path at runtime David Marchand 2020-10-19 13:48 ` [dpdk-dev] [PATCH v10 18/18] acl: check max SIMD bitwidth David Marchand 2020-10-19 14:41 ` [dpdk-dev] [PATCH v10 00/18] add max SIMD bitwidth to EAL David Marchand
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