[dpdk-dev] [PATCH 5/7] net/i40e/base: reduce wait time for adminq command

Jingjing Wu jingjing.wu at intel.com
Wed Mar 22 10:24:57 CET 2017


When sending an adminq command, we wait for the command to complete in
a loop. This loop waits for an entire millisecond, when in practice the
adminq command is processed often much faster.

Change the loop to use i40e_usec_delay instead, and wait for 50 usecs
each time instead. This appears to be about the minimum time required,
based on some manual observation and testing.

The primary benefit of this change is reducing latency of various
operations in the PF driver, especially when related to having a large
number of VFs enabled.

Signed-off-by: Jingjing Wu <jingjing.wu at intel.com>
---
 drivers/net/i40e/base/i40e_adminq.c | 4 ++--
 drivers/net/i40e/base/i40e_adminq.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/i40e/base/i40e_adminq.c b/drivers/net/i40e/base/i40e_adminq.c
index 5bdf3f7..a60292a 100644
--- a/drivers/net/i40e/base/i40e_adminq.c
+++ b/drivers/net/i40e/base/i40e_adminq.c
@@ -944,8 +944,8 @@ enum i40e_status_code i40e_asq_send_command(struct i40e_hw *hw,
 			 */
 			if (i40e_asq_done(hw))
 				break;
-			i40e_msec_delay(1);
-			total_delay++;
+			i40e_usec_delay(50);
+			total_delay += 50;
 		} while (total_delay < hw->aq.asq_cmd_timeout);
 	}
 
diff --git a/drivers/net/i40e/base/i40e_adminq.h b/drivers/net/i40e/base/i40e_adminq.h
index 750973c..182e40b 100644
--- a/drivers/net/i40e/base/i40e_adminq.h
+++ b/drivers/net/i40e/base/i40e_adminq.h
@@ -158,9 +158,9 @@ STATIC INLINE int i40e_aq_rc_to_posix(int aq_ret, int aq_rc)
 
 /* general information */
 #define I40E_AQ_LARGE_BUF	512
-#define I40E_ASQ_CMD_TIMEOUT	250  /* msecs */
+#define I40E_ASQ_CMD_TIMEOUT	250000  /* usecs */
 #ifdef I40E_ESS_SUPPORT
-#define I40E_ASQ_CMD_TIMEOUT_ESS	50000  /* msecs */
+#define I40E_ASQ_CMD_TIMEOUT_ESS	50000000  /* usecs */
 #endif
 
 void i40e_fill_default_direct_cmd_desc(struct i40e_aq_desc *desc,
-- 
2.4.11



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