[dpdk-dev] [PATCH v5 01/17] eal: add max SIMD bitwidth
Ruifeng Wang
Ruifeng.Wang at arm.com
Wed Oct 14 10:50:42 CEST 2020
> -----Original Message-----
> From: Ciara Power <ciara.power at intel.com>
> Sent: Tuesday, October 13, 2020 7:04 PM
> To: dev at dpdk.org
> Cc: viktorin at rehivetech.com; Ruifeng Wang <Ruifeng.Wang at arm.com>;
> jerinj at marvell.com; drc at linux.vnet.ibm.com; bruce.richardson at intel.com;
> konstantin.ananyev at intel.com; Ciara Power <ciara.power at intel.com>;
> Honnappa Nagarahalli <Honnappa.Nagarahalli at arm.com>; Dmitry Kozlyuk
> <dmitry.kozliuk at gmail.com>; Narcisa Ana Maria Vasile
> <navasile at linux.microsoft.com>; Dmitry Malloy <dmitrym at microsoft.com>;
> Pallavi Kadam <pallavi.kadam at intel.com>; Ray Kinsella <mdr at ashroe.eu>;
> Neil Horman <nhorman at tuxdriver.com>
> Subject: [PATCH v5 01/17] eal: add max SIMD bitwidth
>
> 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.wang at arm.com>
> Cc: Jerin Jacob <jerinj at marvell.com>
> Cc: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
> Cc: David Christensen <drc at linux.vnet.ibm.com>
>
> Signed-off-by: Ciara Power <ciara.power at intel.com>
>
> ---
> 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.
> ---
> 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 +
> 9 files changed, 126 insertions(+)
>
> diff --git a/lib/librte_eal/arm/include/rte_vect.h
> b/lib/librte_eal/arm/include/rte_vect.h
> index 01c51712a1..f53c89be97 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 13f93388a7..0c880cbe17 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 7b35beb702..81e99b00d9 100644
> --- a/lib/librte_eal/rte_eal_exports.def
> +++ b/lib/librte_eal/rte_eal_exports.def
> @@ -26,6 +26,7 @@ EXPORTS
> rte_eal_tailq_register
> rte_eal_using_phys_addrs
> rte_free
> + rte_get_max_simd_bitwidth
> rte_get_tsc_hz
> rte_hexdump
> rte_intr_rx_ctl
> @@ -62,6 +63,7 @@ EXPORTS
> rte_memzone_reserve_aligned
> rte_memzone_reserve_bounded
> rte_memzone_walk
> + rte_set_max_simd_bitwidth
> rte_socket_id
> rte_strerror
> rte_strsplit
> diff --git a/lib/librte_eal/rte_eal_version.map
> b/lib/librte_eal/rte_eal_version.map
> index a93dea9fe6..714be49377 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -400,6 +400,8 @@ EXPERIMENTAL {
> # added in 20.11
> __rte_eal_trace_generic_size_t;
> rte_service_lcore_may_be_active;
> + rte_get_max_simd_bitwidth;
> + 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 df5a607623..a00d3d5a62 100644
> --- a/lib/librte_eal/x86/include/rte_vect.h
> +++ b/lib/librte_eal/x86/include/rte_vect.h
> @@ -35,6 +35,8 @@
> extern "C" {
> #endif
>
> +#define RTE_DEFAULT_SIMD_BITWIDTH RTE_SIMD_256
> +
> typedef __m128i xmm_t;
>
> #define XMM_SIZE (sizeof(xmm_t))
> --
> 2.22.0
Arm SVE may not perfectly fit into this. Because SIMD bitwidth is unknown / unconcerned by application.
I think vector path will be taken when max SIMD bitwidth is not set to RTE_SIMD_DISABLED.
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
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