svn commit: r352993 - head/sys/dev/mlx5/mlx5_core

[Hans Petter Selasky]

Author: hselasky
Date: Wed Oct  2 10:59:44 2019
New Revision: 352993
URL: https://svnweb.freebsd.org/changeset/base/352993

Log:
  Randomize the delay when waiting for VSC flag in mlx5core.
  
  The PRM suggests random 0 - 10ms to prevent multiple waiters on the same
  interval in order to avoid starvation.
  
  Submitted by:	slavash@
  MFC after:	3 days
  Sponsored by:	Mellanox Technologies

Modified:
  head/sys/dev/mlx5/mlx5_core/mlx5_vsc.c

Modified: head/sys/dev/mlx5/mlx5_core/mlx5_vsc.c
==============================================================================
--- head/sys/dev/mlx5/mlx5_core/mlx5_vsc.c	Wed Oct  2 10:58:27 2019	(r352992)
+++ head/sys/dev/mlx5/mlx5_core/mlx5_vsc.c	Wed Oct  2 10:59:44 2019	(r352993)
@@ -52,7 +52,7 @@ int mlx5_vsc_lock(struct mlx5_core_dev *mdev)
 			 * The PRM suggests random 0 - 10ms to prevent multiple
 			 * waiters on the same interval in order to avoid starvation
 			 */
-			DELAY((random() % 11) * 1000);
+			DELAY((random() % 9000) + 1000);
 			continue;
 		}
 
@@ -99,7 +99,7 @@ mlx5_vsc_wait_on_flag(struct mlx5_core_dev *mdev, u32 
 			break;
 
 		retries++;
-		DELAY(10);
+		DELAY((random() % 90) + 10);
 	}
 
 	return 0;