[dpdk-dev] [PATCH 20.11 01/12] eal: add max SIMD bitwidth

[Ciara Power <ciara.power@intel.com>]

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.

Signed-off-by: Ciara Power <ciara.power@intel.com>
---
 lib/librte_eal/common/eal_common_options.c | 60 ++++++++++++++++++++++
 lib/librte_eal/common/eal_internal_cfg.h   |  8 +++
 lib/librte_eal/common/eal_options.h        |  2 +
 lib/librte_eal/include/rte_eal.h           | 31 +++++++++++
 lib/librte_eal/rte_eal_version.map         |  4 ++
 5 files changed, 105 insertions(+)

diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
index a5426e1234..90f4e8f5c3 100644
--- a/lib/librte_eal/common/eal_common_options.c
+++ b/lib/librte_eal/common/eal_common_options.c
@@ -102,6 +102,7 @@ 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                        }
 };
 
@@ -1309,6 +1310,32 @@ eal_parse_iova_mode(const char *name)
 	return 0;
 }
 
+static int
+eal_parse_simd_bitwidth(const char *arg, bool locked)
+{
+	char *end;
+	uint16_t 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'))
+		return -1;
+
+	ret = rte_set_max_simd_bitwidth(bitwidth);
+	if (ret < 0)
+		return -1;
+	internal_conf->max_simd_bitwidth.locked = locked;
+	return 0;
+}
+
 static int
 eal_parse_base_virtaddr(const char *arg)
 {
@@ -1707,6 +1734,13 @@ 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, 1) < 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 +1937,31 @@ 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.locked) {
+		RTE_LOG(NOTICE, EAL, "Cannot set max SIMD bitwidth - user runtime override enabled");
+		return -EPERM;
+	}
+	if (bitwidth < RTE_NO_SIMD || !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 +2040,7 @@ 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..367e0cc19e 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 {
+	/**< flag indicating if bitwidth is locked from further modification */
+	bool locked;
+	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 */
+	/** max simd bitwidth path to use */
+	struct simd_bitwidth max_simd_bitwidth;
 };
 
 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 ddcf6a2e7a..14048fdb74 100644
--- a/lib/librte_eal/include/rte_eal.h
+++ b/lib/librte_eal/include/rte_eal.h
@@ -43,6 +43,13 @@ enum rte_proc_type_t {
 	RTE_PROC_INVALID
 };
 
+enum rte_max_simd_t {
+	RTE_NO_SIMD = 64,
+	RTE_MAX_128_SIMD = 128,
+	RTE_MAX_256_SIMD = 256,
+	RTE_MAX_512_SIMD = 512
+};
+
 /**
  * Get the process type in a multi-process setup
  *
@@ -51,6 +58,30 @@ 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.
+ *
+ * @param bitwidth
+ *   uint16_t bitwidth.
+ * @return
+ *   0 on success.
+ * @return
+ *   -EINVAL on invalid bitwidth parameter.
+ * @return
+ *   -EPERM if bitwidth is locked.
+ */
+__rte_experimental
+int rte_set_max_simd_bitwidth(uint16_t bitwidth);
+
 /**
  * Request iopl privilege for all RPL.
  *
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index bf0c17c233..8059ea76b6 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -403,6 +403,10 @@ EXPERIMENTAL {
 	rte_mp_disable;
 	rte_thread_register;
 	rte_thread_unregister;
+
+	# added in 20.11
+	rte_get_max_simd_bitwidth;
+	rte_set_max_simd_bitwidth;
 };
 
 INTERNAL {
-- 
2.17.1