On 16/10/2020 15:27, Ciara Power wrote:
> This patch adds a max SIMD bitwidth EAL configuration. The API allows
> for an app to set this value. It can also be set using EAL argument
> --force-max-simd-bitwidth, which will lock the value and override any
> modifications made by the app.
>
> Each arch has a define for the default SIMD bitwidth value, this is used
> on EAL init to set the config max SIMD bitwidth.
>
> Cc: Ruifeng Wang <ruifeng.w...@arm.com>
> Cc: Jerin Jacob <jer...@marvell.com>
> Cc: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> Cc: David Christensen <d...@linux.vnet.ibm.com>
>
> Signed-off-by: Ciara Power <ciara.po...@intel.com>
> Acked-by: Konstantin Ananyev <konstantin.anan...@intel.com>
> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
>
> ---
> v9: Added release note.
> v7: Reordered entries in the symbol .map file.
> v4:
> - Used RTE_SIMD_MAX instead of UINT16_MAX.
> - Renamed enums to better reflect usage.
> - Added functions to windows symbol export file.
> - Modified Doxygen comments.
> - Modified enum name.
> - Changed RTE_SIMD_MAX value to a power of 2.
> - Merged patch 2 into this patch.
> - Enum now used for default value defines.
> - Fixed some small comments on v3.
> v3:
> - Added enum value to essentially disable using max SIMD to choose
> paths, intended for use by ARM SVE.
> - Fixed parsing bitwidth argument to return an error for values
> greater than uint16_t.
> - Removed unnecessary define in generic rte_vect.h
> - Changed default bitwidth for ARM to UINT16_MAX, to allow for SVE.
> v2:
> - Added to Doxygen comment for API.
> - Changed default bitwidth for Arm to 128.
> ---
> doc/guides/rel_notes/release_20_11.rst | 6 ++
> lib/librte_eal/arm/include/rte_vect.h | 2 +
> lib/librte_eal/common/eal_common_options.c | 66 ++++++++++++++++++++++
> lib/librte_eal/common/eal_internal_cfg.h | 8 +++
> lib/librte_eal/common/eal_options.h | 2 +
> lib/librte_eal/include/rte_eal.h | 40 +++++++++++++
> lib/librte_eal/ppc/include/rte_vect.h | 2 +
> lib/librte_eal/rte_eal_exports.def | 2 +
> lib/librte_eal/rte_eal_version.map | 2 +
> lib/librte_eal/x86/include/rte_vect.h | 2 +
> 10 files changed, 132 insertions(+)
>
> diff --git a/doc/guides/rel_notes/release_20_11.rst
> b/doc/guides/rel_notes/release_20_11.rst
> index 48717ee536..4d2b949a6e 100644
> --- a/doc/guides/rel_notes/release_20_11.rst
> +++ b/doc/guides/rel_notes/release_20_11.rst
> @@ -77,6 +77,12 @@ New Features
> This API is specific to x86 and implemented as a stub for other
> architectures.
>
> +* **Added support for limiting maximum SIMD bitwidth.**
> +
> + Added a new EAL config setting ``max_simd_bitwidth`` to limit the vector
> + path selection at runtime. This value can be set by apps using the
> + ``rte_set_max_simd_bitwidth`` function, or by the user with EAL flag
> ``--force-max-simd-bitwidth``.
> +
> * **Updated CRC modules of the net library.**
>
> * Added runtime selection of the optimal architecture-specific CRC path.
> diff --git a/lib/librte_eal/arm/include/rte_vect.h
> b/lib/librte_eal/arm/include/rte_vect.h
> index f6a455b4e7..df8fb8b670 100644
> --- a/lib/librte_eal/arm/include/rte_vect.h
> +++ b/lib/librte_eal/arm/include/rte_vect.h
> @@ -14,6 +14,8 @@
> extern "C" {
> #endif
>
> +#define RTE_DEFAULT_SIMD_BITWIDTH RTE_SIMD_MAX
> +
> typedef int32x4_t xmm_t;
>
> #define XMM_SIZE (sizeof(xmm_t))
> diff --git a/lib/librte_eal/common/eal_common_options.c
> b/lib/librte_eal/common/eal_common_options.c
> index a5426e1234..8c79f1b2fc 100644
> --- a/lib/librte_eal/common/eal_common_options.c
> +++ b/lib/librte_eal/common/eal_common_options.c
> @@ -35,6 +35,7 @@
> #ifndef RTE_EXEC_ENV_WINDOWS
> #include <rte_telemetry.h>
> #endif
> +#include <rte_vect.h>
>
> #include "eal_internal_cfg.h"
> #include "eal_options.h"
> @@ -102,6 +103,7 @@ eal_long_options[] = {
> {OPT_MATCH_ALLOCATIONS, 0, NULL, OPT_MATCH_ALLOCATIONS_NUM},
> {OPT_TELEMETRY, 0, NULL, OPT_TELEMETRY_NUM },
> {OPT_NO_TELEMETRY, 0, NULL, OPT_NO_TELEMETRY_NUM },
> + {OPT_FORCE_MAX_SIMD_BITWIDTH, 1, NULL, OPT_FORCE_MAX_SIMD_BITWIDTH_NUM},
> {0, 0, NULL, 0 }
> };
>
> @@ -343,6 +345,8 @@ eal_reset_internal_config(struct internal_config
> *internal_cfg)
> internal_cfg->user_mbuf_pool_ops_name = NULL;
> CPU_ZERO(&internal_cfg->ctrl_cpuset);
> internal_cfg->init_complete = 0;
> + internal_cfg->max_simd_bitwidth.bitwidth = RTE_DEFAULT_SIMD_BITWIDTH;
> + internal_cfg->max_simd_bitwidth.forced = 0;
> }
>
> static int
> @@ -1309,6 +1313,34 @@ eal_parse_iova_mode(const char *name)
> return 0;
> }
>
> +static int
> +eal_parse_simd_bitwidth(const char *arg)
> +{
> + char *end;
> + unsigned long bitwidth;
> + int ret;
> + struct internal_config *internal_conf =
> + eal_get_internal_configuration();
> +
> + if (arg == NULL || arg[0] == '\0')
> + return -1;
> +
> + errno = 0;
> + bitwidth = strtoul(arg, &end, 0);
> +
> + /* check for errors */
> + if (errno != 0 || end == NULL || *end != '\0' || bitwidth >
> RTE_SIMD_MAX)
> + return -1;
> +
> + if (bitwidth == 0)
> + bitwidth = (unsigned long) RTE_SIMD_MAX;
> + ret = rte_set_max_simd_bitwidth(bitwidth);
> + if (ret < 0)
> + return -1;
> + internal_conf->max_simd_bitwidth.forced = 1;
> + return 0;
> +}
> +
> static int
> eal_parse_base_virtaddr(const char *arg)
> {
> @@ -1707,6 +1739,13 @@ eal_parse_common_option(int opt, const char *optarg,
> case OPT_NO_TELEMETRY_NUM:
> conf->no_telemetry = 1;
> break;
> + case OPT_FORCE_MAX_SIMD_BITWIDTH_NUM:
> + if (eal_parse_simd_bitwidth(optarg) < 0) {
> + RTE_LOG(ERR, EAL, "invalid parameter for --"
> + OPT_FORCE_MAX_SIMD_BITWIDTH "\n");
> + return -1;
> + }
> + break;
>
> /* don't know what to do, leave this to caller */
> default:
> @@ -1903,6 +1942,32 @@ eal_check_common_options(struct internal_config
> *internal_cfg)
> return 0;
> }
>
> +uint16_t
> +rte_get_max_simd_bitwidth(void)
> +{
> + const struct internal_config *internal_conf =
> + eal_get_internal_configuration();
> + return internal_conf->max_simd_bitwidth.bitwidth;
> +}
> +
> +int
> +rte_set_max_simd_bitwidth(uint16_t bitwidth)
> +{
> + struct internal_config *internal_conf =
> + eal_get_internal_configuration();
> + if (internal_conf->max_simd_bitwidth.forced) {
> + RTE_LOG(NOTICE, EAL, "Cannot set max SIMD bitwidth - user
> runtime override enabled");
> + return -EPERM;
> + }
> +
> + if (bitwidth < RTE_SIMD_DISABLED || !rte_is_power_of_2(bitwidth)) {
> + RTE_LOG(ERR, EAL, "Invalid bitwidth value!\n");
> + return -EINVAL;
> + }
> + internal_conf->max_simd_bitwidth.bitwidth = bitwidth;
> + return 0;
> +}
> +
> void
> eal_common_usage(void)
> {
> @@ -1981,6 +2046,7 @@ eal_common_usage(void)
> " --"OPT_BASE_VIRTADDR" Base virtual address\n"
> " --"OPT_TELEMETRY" Enable telemetry support (on by
> default)\n"
> " --"OPT_NO_TELEMETRY" Disable telemetry support\n"
> + " --"OPT_FORCE_MAX_SIMD_BITWIDTH" Force the max SIMD bitwidth\n"
> "\nEAL options for DEBUG use only:\n"
> " --"OPT_HUGE_UNLINK" Unlink hugepage files after init\n"
> " --"OPT_NO_HUGE" Use malloc instead of hugetlbfs\n"
> diff --git a/lib/librte_eal/common/eal_internal_cfg.h
> b/lib/librte_eal/common/eal_internal_cfg.h
> index de627c7627..51dbe86e2b 100644
> --- a/lib/librte_eal/common/eal_internal_cfg.h
> +++ b/lib/librte_eal/common/eal_internal_cfg.h
> @@ -33,6 +33,12 @@ struct hugepage_info {
> int lock_descriptor; /**< file descriptor for hugepage dir */
> };
>
> +struct simd_bitwidth {
> + bool forced;
> + /**< flag indicating if bitwidth is forced and can't be modified */
> + uint16_t bitwidth; /**< bitwidth value */
> +};
> +
> /**
> * internal configuration
> */
> @@ -85,6 +91,8 @@ struct internal_config {
> volatile unsigned int init_complete;
> /**< indicates whether EAL has completed initialization */
> unsigned int no_telemetry; /**< true to disable Telemetry */
> + struct simd_bitwidth max_simd_bitwidth;
> + /**< max simd bitwidth path to use */
> };
>
> void eal_reset_internal_config(struct internal_config *internal_cfg);
> diff --git a/lib/librte_eal/common/eal_options.h
> b/lib/librte_eal/common/eal_options.h
> index 89769d48b4..ef33979664 100644
> --- a/lib/librte_eal/common/eal_options.h
> +++ b/lib/librte_eal/common/eal_options.h
> @@ -85,6 +85,8 @@ enum {
> OPT_TELEMETRY_NUM,
> #define OPT_NO_TELEMETRY "no-telemetry"
> OPT_NO_TELEMETRY_NUM,
> +#define OPT_FORCE_MAX_SIMD_BITWIDTH "force-max-simd-bitwidth"
> + OPT_FORCE_MAX_SIMD_BITWIDTH_NUM,
> OPT_LONG_MAX_NUM
> };
>
> diff --git a/lib/librte_eal/include/rte_eal.h
> b/lib/librte_eal/include/rte_eal.h
> index e3c2ef185e..706d3cca5a 100644
> --- a/lib/librte_eal/include/rte_eal.h
> +++ b/lib/librte_eal/include/rte_eal.h
> @@ -43,6 +43,23 @@ enum rte_proc_type_t {
> RTE_PROC_INVALID
> };
>
> +/**
> + * The max SIMD bitwidth value to limit vector path selection.
> + */
> +enum rte_max_simd {
> + RTE_SIMD_DISABLED = 64,
> + /**< Limits path selection to scalar, disables all vector paths. */
> + RTE_SIMD_128 = 128,
> + /**< Limits path selection to SSE/NEON/Altivec or below. */
> + RTE_SIMD_256 = 256, /**< Limits path selection to AVX2 or below. */
> + RTE_SIMD_512 = 512, /**< Limits path selection to AVX512 or below. */
> + RTE_SIMD_MAX = INT16_MAX + 1,
> + /**<
> + * Disables limiting by max SIMD bitwidth, allows all suitable paths.
> + * This value is used as it is a large number and a power of 2.
> + */
> +};
> +
> /**
> * Get the process type in a multi-process setup
> *
> @@ -51,6 +68,29 @@ enum rte_proc_type_t {
> */
> enum rte_proc_type_t rte_eal_process_type(void);
>
> +/**
> + * Get the supported SIMD bitwidth.
> + *
> + * @return
> + * uint16_t bitwidth.
> + */
> +__rte_experimental
> +uint16_t rte_get_max_simd_bitwidth(void);
> +
> +/**
> + * Set the supported SIMD bitwidth.
> + * This API should only be called once at initialization, before EAL init.
> + *
> + * @param bitwidth
> + * uint16_t bitwidth.
> + * @return
> + * - 0 on success.
> + * - -EINVAL on invalid bitwidth parameter.
> + * - -EPERM if bitwidth is forced.
> + */
> +__rte_experimental
> +int rte_set_max_simd_bitwidth(uint16_t bitwidth);
> +
> /**
> * Request iopl privilege for all RPL.
> *
> diff --git a/lib/librte_eal/ppc/include/rte_vect.h
> b/lib/librte_eal/ppc/include/rte_vect.h
> index b0545c878c..a69aabc568 100644
> --- a/lib/librte_eal/ppc/include/rte_vect.h
> +++ b/lib/librte_eal/ppc/include/rte_vect.h
> @@ -15,6 +15,8 @@
> extern "C" {
> #endif
>
> +#define RTE_DEFAULT_SIMD_BITWIDTH RTE_SIMD_256
> +
> typedef vector signed int xmm_t;
>
> #define XMM_SIZE (sizeof(xmm_t))
> diff --git a/lib/librte_eal/rte_eal_exports.def
> b/lib/librte_eal/rte_eal_exports.def
> index 975acb8ffe..b61e9a0f6e 100644
> --- a/lib/librte_eal/rte_eal_exports.def
> +++ b/lib/librte_eal/rte_eal_exports.def
> @@ -59,6 +59,7 @@ EXPORTS
> rte_exit
> rte_free
> rte_get_master_lcore
> + rte_get_max_simd_bitwidth
> rte_get_next_lcore
> rte_get_tsc_hz
> rte_hexdump
> @@ -147,6 +148,7 @@ EXPORTS
> rte_service_set_stats_enable
> rte_service_start_with_defaults
> rte_set_application_usage_hook
> + rte_set_max_simd_bitwidth
> rte_socket_count
> rte_socket_id
> rte_socket_id_by_idx
> diff --git a/lib/librte_eal/rte_eal_version.map
> b/lib/librte_eal/rte_eal_version.map
> index f56de02d8f..80f6911322 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -398,7 +398,9 @@ EXPERIMENTAL {
>
> # added in 20.11
> __rte_eal_trace_generic_size_t;
> + rte_get_max_simd_bitwidth;
> rte_service_lcore_may_be_active;
> + rte_set_max_simd_bitwidth;
> };
>
> INTERNAL {
> diff --git a/lib/librte_eal/x86/include/rte_vect.h
> b/lib/librte_eal/x86/include/rte_vect.h
> index 64383c3606..f0aad9615e 100644
> --- a/lib/librte_eal/x86/include/rte_vect.h
> +++ b/lib/librte_eal/x86/include/rte_vect.h
> @@ -36,6 +36,8 @@
> extern "C" {
> #endif
>
> +#define RTE_DEFAULT_SIMD_BITWIDTH RTE_SIMD_256
> +
> typedef __m128i xmm_t;
>
> #define XMM_SIZE (sizeof(xmm_t))
>
Acked-by: Ray Kinsella <m...@ashroe.eu>
