[dpdk-dev] [PATCH v6 1/3] i40e: Use constant as the default hash keys

[Helin Zhang]

Calculating the default RSS hash keys at run time is not needed at
all, and may have race conditions. The alternative is to use array
of random values which were generated manually as the default hash
keys.

Signed-off-by: Helin Zhang <helin.zhang at intel.com>
---
 lib/librte_pmd_i40e/i40e_ethdev.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/librte_pmd_i40e/i40e_ethdev.c b/lib/librte_pmd_i40e/i40e_ethdev.c
index 5074262..9096802 100644
--- a/lib/librte_pmd_i40e/i40e_ethdev.c
+++ b/lib/librte_pmd_i40e/i40e_ethdev.c
@@ -92,7 +92,7 @@
 #define I40E_48_BIT_SHIFT 48
 #define I40E_48_BIT_MASK  0xFFFFFFFFFFFFULL
 
-/* Default queue interrupt throttling time in microseconds*/
+/* Default queue interrupt throttling time in microseconds */
 #define I40E_ITR_INDEX_DEFAULT          0
 #define I40E_QUEUE_ITR_INTERVAL_DEFAULT 32 /* 32 us */
 #define I40E_QUEUE_ITR_INTERVAL_MAX     8160 /* 8160 us */
@@ -210,9 +210,6 @@ static int i40e_dev_filter_ctrl(struct rte_eth_dev *dev,
 				enum rte_filter_op filter_op,
 				void *arg);
 
-/* Default hash key buffer for RSS */
-static uint32_t rss_key_default[I40E_PFQF_HKEY_MAX_INDEX + 1];
-
 static struct rte_pci_id pci_id_i40e_map[] = {
 #define RTE_PCI_DEV_ID_DECL_I40E(vend, dev) {RTE_PCI_DEVICE(vend, dev)},
 #include "rte_pci_dev_ids.h"
@@ -4893,9 +4890,12 @@ i40e_pf_config_rss(struct i40e_pf *pf)
 	}
 	if (rss_conf.rss_key == NULL || rss_conf.rss_key_len <
 		(I40E_PFQF_HKEY_MAX_INDEX + 1) * sizeof(uint32_t)) {
-		/* Calculate the default hash key */
-		for (i = 0; i <= I40E_PFQF_HKEY_MAX_INDEX; i++)
-			rss_key_default[i] = (uint32_t)rte_rand();
+		/* Random default keys */
+		static uint32_t rss_key_default[] = {0x6b793944,
+			0x23504cb5, 0x5bea75b6, 0x309f4f12, 0x3dc0a2b8,
+			0x024ddcdf, 0x339b8ca0, 0x4c4af64a, 0x34fac605,
+			0x55d85839, 0x3a58997d, 0x2ec938e1, 0x66031581};
+
 		rss_conf.rss_key = (uint8_t *)rss_key_default;
 		rss_conf.rss_key_len = (I40E_PFQF_HKEY_MAX_INDEX + 1) *
 							sizeof(uint32_t);
-- 
1.8.1.4