svn commit: r235393 - stable/9/sys/dev/e1000

[Sean Bruno]

Author: sbruno
Date: Sun May 13 10:31:08 2012
New Revision: 235393
URL: http://svn.freebsd.org/changeset/base/235393

Log:
  MFC 235210
  
    Modify the binding of queues to attach to as many CPUs
    as possible when using more than one igb(4) adapter.  This
    means that queues will not be bound to the same CPUs if
    there are more CPUs availble.
  
    This is only applicable to a system that has multiple interfaces.

Modified:
  stable/9/sys/dev/e1000/if_igb.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/dev/e1000/if_igb.c
==============================================================================
--- stable/9/sys/dev/e1000/if_igb.c	Sun May 13 09:27:08 2012	(r235392)
+++ stable/9/sys/dev/e1000/if_igb.c	Sun May 13 10:31:08 2012	(r235393)
@@ -362,6 +362,13 @@ TUNABLE_INT("hw.igb.num_queues", &igb_nu
 SYSCTL_INT(_hw_igb, OID_AUTO, num_queues, CTLFLAG_RDTUN, &igb_num_queues, 0,
     "Number of queues to configure, 0 indicates autoconfigure");
 
+/*
+** Global variable to store last used CPU when binding queues
+** to CPUs in igb_allocate_msix.  Starts at CPU_FIRST and increments when a
+** queue is bound to a cpu.
+*/
+static int igb_last_bind_cpu = -1;
+
 /* How many packets rxeof tries to clean at a time */
 static int igb_rx_process_limit = 100;
 TUNABLE_INT("hw.igb.rx_process_limit", &igb_rx_process_limit);
@@ -2323,8 +2330,16 @@ igb_allocate_msix(struct adapter *adapte
 		** Bind the msix vector, and thus the
 		** rings to the corresponding cpu.
 		*/
-		if (adapter->num_queues > 1)
-			bus_bind_intr(dev, que->res, i);
+		if (adapter->num_queues > 1) {
+			if (igb_last_bind_cpu < 0)
+				igb_last_bind_cpu = CPU_FIRST();
+			bus_bind_intr(dev, que->res, igb_last_bind_cpu);
+			device_printf(dev,
+				"Bound queue %d to cpu %d\n",
+				i,igb_last_bind_cpu);
+			igb_last_bind_cpu = CPU_NEXT(igb_last_bind_cpu);
+			igb_last_bind_cpu = igb_last_bind_cpu % mp_ncpus;
+		}
 #if __FreeBSD_version >= 800000
 		TASK_INIT(&que->txr->txq_task, 0, igb_deferred_mq_start,
 		    que->txr);