[PATCH] e1000: dynamic itr: take TSO and jumbo into account
Jesse Brandeburg [Fri, 15 Dec 2006 09:30:44 +0000 (10:30 +0100)]
The dynamic interrupt rate control patches omitted proper counting
for jumbo's and TSO resulting in suboptimal interrupt mitigation strategies.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/e1000/e1000_main.c

index 73f3a85..62ef267 100644 (file)
@@ -2628,29 +2628,34 @@ static unsigned int e1000_update_itr(struct e1000_adapter *adapter,
        if (packets == 0)
                goto update_itr_done;
 
-
        switch (itr_setting) {
        case lowest_latency:
-               if ((packets < 5) && (bytes > 512))
+               /* jumbo frames get bulk treatment*/
+               if (bytes/packets > 8000)
+                       retval = bulk_latency;
+               else if ((packets < 5) && (bytes > 512))
                        retval = low_latency;
                break;
        case low_latency:  /* 50 usec aka 20000 ints/s */
                if (bytes > 10000) {
-                       if ((packets < 10) ||
-                            ((bytes/packets) > 1200))
+                       /* jumbo frames need bulk latency setting */
+                       if (bytes/packets > 8000)
+                               retval = bulk_latency;
+                       else if ((packets < 10) || ((bytes/packets) > 1200))
                                retval = bulk_latency;
                        else if ((packets > 35))
                                retval = lowest_latency;
-               } else if (packets <= 2 && bytes < 512)
+               } else if (bytes/packets > 2000)
+                       retval = bulk_latency;
+               else if (packets <= 2 && bytes < 512)
                        retval = lowest_latency;
                break;
        case bulk_latency: /* 250 usec aka 4000 ints/s */
                if (bytes > 25000) {
                        if (packets > 35)
                                retval = low_latency;
-               } else {
-                       if (bytes < 6000)
-                               retval = low_latency;
+               } else if (bytes < 6000) {
+                       retval = low_latency;
                }
                break;
        }
@@ -2679,17 +2684,20 @@ static void e1000_set_itr(struct e1000_adapter *adapter)
                                    adapter->tx_itr,
                                    adapter->total_tx_packets,
                                    adapter->total_tx_bytes);
+       /* conservative mode (itr 3) eliminates the lowest_latency setting */
+       if (adapter->itr_setting == 3 && adapter->tx_itr == lowest_latency)
+               adapter->tx_itr = low_latency;
+
        adapter->rx_itr = e1000_update_itr(adapter,
                                    adapter->rx_itr,
                                    adapter->total_rx_packets,
                                    adapter->total_rx_bytes);
+       /* conservative mode (itr 3) eliminates the lowest_latency setting */
+       if (adapter->itr_setting == 3 && adapter->rx_itr == lowest_latency)
+               adapter->rx_itr = low_latency;
 
        current_itr = max(adapter->rx_itr, adapter->tx_itr);
 
-       /* conservative mode eliminates the lowest_latency setting */
-       if (current_itr == lowest_latency && (adapter->itr_setting == 3))
-               current_itr = low_latency;
-
        switch (current_itr) {
        /* counts and packets in update_itr are dependent on these numbers */
        case lowest_latency:
@@ -3868,11 +3876,11 @@ e1000_clean_tx_irq(struct e1000_adapter *adapter,
                        cleaned = (i == eop);
 
                        if (cleaned) {
-                               /* this packet count is wrong for TSO but has a
-                                * tendency to make dynamic ITR change more
-                                * towards bulk */
+                               struct sk_buff *skb = buffer_info->skb;
+                               unsigned int segs = skb_shinfo(skb)->gso_segs;
+                               total_tx_packets += segs;
                                total_tx_packets++;
-                               total_tx_bytes += buffer_info->skb->len;
+                               total_tx_bytes += skb->len;
                        }
                        e1000_unmap_and_free_tx_resource(adapter, buffer_info);
                        tx_desc->upper.data = 0;