ixgbe: Make better use of memory allocations in one-buffer mode w/ RSC
This patch improves the memory utilization with RSC when in one-buffer
mode. This is accomplished by making the default buffer sizes match up
with the standard memory allocation sizes minus 1K for shared info and
padding overhead. By doing this CPU utilization when doing large receives
can be reduced by as much as 8%.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index ce59dc6..a4103ef 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -499,7 +499,7 @@
rx_ring->rx_buf_len, true);
if (rx_ring->rx_buf_len
- < IXGBE_RXBUFFER_2048)
+ < IXGBE_RXBUFFER_2K)
print_hex_dump(KERN_INFO, "",
DUMP_PREFIX_ADDRESS, 16, 1,
phys_to_virt(
@@ -2644,9 +2644,9 @@
rscctrl |= IXGBE_RSCCTL_MAXDESC_1;
#endif
} else {
- if (rx_buf_len < IXGBE_RXBUFFER_4096)
+ if (rx_buf_len < IXGBE_RXBUFFER_4K)
rscctrl |= IXGBE_RSCCTL_MAXDESC_16;
- else if (rx_buf_len < IXGBE_RXBUFFER_8192)
+ else if (rx_buf_len < IXGBE_RXBUFFER_8K)
rscctrl |= IXGBE_RSCCTL_MAXDESC_8;
else
rscctrl |= IXGBE_RSCCTL_MAXDESC_4;
@@ -2879,17 +2879,6 @@
if (hw->mac.type == ixgbe_mac_82599EB)
adapter->flags &= ~IXGBE_FLAG_RX_PS_ENABLED;
- /* Set the RX buffer length according to the mode */
- if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) {
- rx_buf_len = IXGBE_RX_HDR_SIZE;
- } else {
- if (!(adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) &&
- (netdev->mtu <= ETH_DATA_LEN))
- rx_buf_len = MAXIMUM_ETHERNET_VLAN_SIZE;
- else
- rx_buf_len = ALIGN(max_frame + VLAN_HLEN, 1024);
- }
-
#ifdef IXGBE_FCOE
/* adjust max frame to be able to do baby jumbo for FCoE */
if ((adapter->flags & IXGBE_FLAG_FCOE_ENABLED) &&
@@ -2905,6 +2894,30 @@
IXGBE_WRITE_REG(hw, IXGBE_MHADD, mhadd);
}
+ /* MHADD will allow an extra 4 bytes past for vlan tagged frames */
+ max_frame += VLAN_HLEN;
+
+ /* Set the RX buffer length according to the mode */
+ if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) {
+ rx_buf_len = IXGBE_RX_HDR_SIZE;
+ } else {
+ if (!(adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) &&
+ (netdev->mtu <= ETH_DATA_LEN))
+ rx_buf_len = MAXIMUM_ETHERNET_VLAN_SIZE;
+ /*
+ * Make best use of allocation by using all but 1K of a
+ * power of 2 allocation that will be used for skb->head.
+ */
+ else if (max_frame <= IXGBE_RXBUFFER_3K)
+ rx_buf_len = IXGBE_RXBUFFER_3K;
+ else if (max_frame <= IXGBE_RXBUFFER_7K)
+ rx_buf_len = IXGBE_RXBUFFER_7K;
+ else if (max_frame <= IXGBE_RXBUFFER_15K)
+ rx_buf_len = IXGBE_RXBUFFER_15K;
+ else
+ rx_buf_len = IXGBE_MAX_RXBUFFER;
+ }
+
hlreg0 = IXGBE_READ_REG(hw, IXGBE_HLREG0);
/* set jumbo enable since MHADD.MFS is keeping size locked at max_frame */
hlreg0 |= IXGBE_HLREG0_JUMBOEN;