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authorAlexander Duyck <alexander.h.duyck@intel.com>2009-05-17 20:57:47 +0000
committerDavid S. Miller <davem@davemloft.net>2009-05-18 15:09:43 -0700
commite76678dd654545c98a5d0bdc66bd41350573c23e (patch)
tree86e4ff745d686f82353c460542e321ba0b09cbc0
parent82d048186e403f36e083b37ad42aa90abb7dcaac (diff)
ixgbe: set max desc to prevent total RSC packet size of 64K
The performance of hardware RSC is greatly reduced if the total for max rsc descriptors multiplied by the buffer size is greater than 65535. To prevent this we need to adjust the max rsc descriptors appropriately. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ixgbe/ixgbe.h2
-rw-r--r--drivers/net/ixgbe/ixgbe_main.c29
2 files changed, 20 insertions, 11 deletions
diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index d291d1cbe04..05a24055ac2 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h
@@ -75,6 +75,8 @@
#define IXGBE_RXBUFFER_128 128 /* Used for packet split */
#define IXGBE_RXBUFFER_256 256 /* Used for packet split */
#define IXGBE_RXBUFFER_2048 2048
+#define IXGBE_RXBUFFER_4096 4096
+#define IXGBE_RXBUFFER_8192 8192
#define IXGBE_MAX_RXBUFFER 16384 /* largest size for a single descriptor */
#define IXGBE_RX_HDR_SIZE IXGBE_RXBUFFER_256
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index b53f2650117..4ab17ab7fbc 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -1995,21 +1995,28 @@ static void ixgbe_configure_rx(struct ixgbe_adapter *adapter)
rscctrl = IXGBE_READ_REG(hw, IXGBE_RSCCTL(j));
rscctrl |= IXGBE_RSCCTL_RSCEN;
/*
- * if packet split is enabled we can only support up
- * to max frags + 1 descriptors.
+ * we must limit the number of descriptors so that the
+ * total size of max desc * buf_len is not greater
+ * than 65535
*/
- if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED)
-#if (MAX_SKB_FRAGS < 3)
- rscctrl |= IXGBE_RSCCTL_MAXDESC_1;
-#elif (MAX_SKB_FRAGS < 7)
- rscctrl |= IXGBE_RSCCTL_MAXDESC_4;
-#elif (MAX_SKB_FRAGS < 15)
+ if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) {
+#if (MAX_SKB_FRAGS > 16)
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_16;
+#elif (MAX_SKB_FRAGS > 8)
rscctrl |= IXGBE_RSCCTL_MAXDESC_8;
+#elif (MAX_SKB_FRAGS > 4)
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_4;
#else
- rscctrl |= IXGBE_RSCCTL_MAXDESC_16;
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_1;
#endif
- else
- rscctrl |= IXGBE_RSCCTL_MAXDESC_16;
+ } else {
+ if (rx_buf_len < IXGBE_RXBUFFER_4096)
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_16;
+ else if (rx_buf_len < IXGBE_RXBUFFER_8192)
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_8;
+ else
+ rscctrl |= IXGBE_RSCCTL_MAXDESC_4;
+ }
IXGBE_WRITE_REG(hw, IXGBE_RSCCTL(j), rscctrl);
}
/* Disable RSC for ACK packets */