e1000: Buffer optimizations for small MTU
Remove multi-descriptor support from legacy recieve path
Add memory usage efficiency by using more correct size descriptors for
small MTU sizes and optimize using LPE for <= 1522 byte frame sizes
An extra performance fix that effected our TCP window size growth
as a receiver. Set our initial buffer to be 128 bytes instead of 256
to prevent over-socket charge when truesize is computed in the stack.
old way: truesize = 256 + l1 = 256 + 1460 = 1716
new way: truesize = 128 + l1 = 128 + 1460 = 1588
The magic value that we can't cross is 1648.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 6d7ba0b..f604a1d 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -972,8 +972,8 @@
pci_read_config_word(pdev, PCI_COMMAND, &hw->pci_cmd_word);
- adapter->rx_buffer_len = E1000_RXBUFFER_2048;
- adapter->rx_ps_bsize0 = E1000_RXBUFFER_256;
+ adapter->rx_buffer_len = MAXIMUM_ETHERNET_FRAME_SIZE;
+ adapter->rx_ps_bsize0 = E1000_RXBUFFER_128;
hw->max_frame_size = netdev->mtu +
ENET_HEADER_SIZE + ETHERNET_FCS_SIZE;
hw->min_frame_size = MINIMUM_ETHERNET_FRAME_SIZE;
@@ -1599,14 +1599,21 @@
rctl |= E1000_RCTL_LPE;
/* Setup buffer sizes */
- if (adapter->hw.mac_type >= e1000_82571) {
- /* We can now specify buffers in 1K increments.
- * BSIZE and BSEX are ignored in this case. */
- rctl |= adapter->rx_buffer_len << 0x11;
- } else {
- rctl &= ~E1000_RCTL_SZ_4096;
- rctl |= E1000_RCTL_BSEX;
- switch (adapter->rx_buffer_len) {
+ rctl &= ~E1000_RCTL_SZ_4096;
+ rctl |= E1000_RCTL_BSEX;
+ switch (adapter->rx_buffer_len) {
+ case E1000_RXBUFFER_256:
+ rctl |= E1000_RCTL_SZ_256;
+ rctl &= ~E1000_RCTL_BSEX;
+ break;
+ case E1000_RXBUFFER_512:
+ rctl |= E1000_RCTL_SZ_512;
+ rctl &= ~E1000_RCTL_BSEX;
+ break;
+ case E1000_RXBUFFER_1024:
+ rctl |= E1000_RCTL_SZ_1024;
+ rctl &= ~E1000_RCTL_BSEX;
+ break;
case E1000_RXBUFFER_2048:
default:
rctl |= E1000_RCTL_SZ_2048;
@@ -1621,7 +1628,6 @@
case E1000_RXBUFFER_16384:
rctl |= E1000_RCTL_SZ_16384;
break;
- }
}
#ifndef CONFIG_E1000_DISABLE_PACKET_SPLIT
@@ -2982,8 +2988,7 @@
/* Adapter-specific max frame size limits. */
switch (adapter->hw.mac_type) {
- case e1000_82542_rev2_0:
- case e1000_82542_rev2_1:
+ case e1000_undefined ... e1000_82542_rev2_1:
if (max_frame > MAXIMUM_ETHERNET_FRAME_SIZE) {
DPRINTK(PROBE, ERR, "Jumbo Frames not supported.\n");
return -EINVAL;
@@ -3017,27 +3022,32 @@
break;
}
+ /* NOTE: dev_alloc_skb reserves 16 bytes, and typically NET_IP_ALIGN
+ * means we reserve 2 more, this pushes us to allocate from the next
+ * larger slab size
+ * i.e. RXBUFFER_2048 --> size-4096 slab */
- if (adapter->hw.mac_type > e1000_82547_rev_2) {
- adapter->rx_buffer_len = max_frame;
- E1000_ROUNDUP(adapter->rx_buffer_len, 1024);
- } else {
- if(unlikely((adapter->hw.mac_type < e1000_82543) &&
- (max_frame > MAXIMUM_ETHERNET_FRAME_SIZE))) {
- DPRINTK(PROBE, ERR, "Jumbo Frames not supported "
- "on 82542\n");
- return -EINVAL;
- } else {
- if(max_frame <= E1000_RXBUFFER_2048)
- adapter->rx_buffer_len = E1000_RXBUFFER_2048;
- else if(max_frame <= E1000_RXBUFFER_4096)
- adapter->rx_buffer_len = E1000_RXBUFFER_4096;
- else if(max_frame <= E1000_RXBUFFER_8192)
- adapter->rx_buffer_len = E1000_RXBUFFER_8192;
- else if(max_frame <= E1000_RXBUFFER_16384)
- adapter->rx_buffer_len = E1000_RXBUFFER_16384;
- }
- }
+ if (max_frame <= E1000_RXBUFFER_256)
+ adapter->rx_buffer_len = E1000_RXBUFFER_256;
+ else if (max_frame <= E1000_RXBUFFER_512)
+ adapter->rx_buffer_len = E1000_RXBUFFER_512;
+ else if (max_frame <= E1000_RXBUFFER_1024)
+ adapter->rx_buffer_len = E1000_RXBUFFER_1024;
+ else if (max_frame <= E1000_RXBUFFER_2048)
+ adapter->rx_buffer_len = E1000_RXBUFFER_2048;
+ else if (max_frame <= E1000_RXBUFFER_4096)
+ adapter->rx_buffer_len = E1000_RXBUFFER_4096;
+ else if (max_frame <= E1000_RXBUFFER_8192)
+ adapter->rx_buffer_len = E1000_RXBUFFER_8192;
+ else if (max_frame <= E1000_RXBUFFER_16384)
+ adapter->rx_buffer_len = E1000_RXBUFFER_16384;
+
+ /* adjust allocation if LPE protects us, and we aren't using SBP */
+#define MAXIMUM_ETHERNET_VLAN_SIZE 1522
+ if (!adapter->hw.tbi_compatibility_on &&
+ ((max_frame == MAXIMUM_ETHERNET_FRAME_SIZE) ||
+ (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE)))
+ adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE;
netdev->mtu = new_mtu;
@@ -3568,10 +3578,12 @@
flags);
length--;
} else {
- dev_kfree_skb_irq(skb);
+ /* recycle */
+ buffer_info->skb = skb;
goto next_desc;
}
- }
+ } else
+ skb_put(skb, length);
/* code added for copybreak, this should improve
* performance for small packets with large amounts
@@ -3676,6 +3688,7 @@
i = rx_ring->next_to_clean;
rx_desc = E1000_RX_DESC_PS(*rx_ring, i);
staterr = le32_to_cpu(rx_desc->wb.middle.status_error);
+ buffer_info = &rx_ring->buffer_info[i];
while (staterr & E1000_RXD_STAT_DD) {
buffer_info = &rx_ring->buffer_info[i];
@@ -3736,7 +3749,7 @@
/* page alloc/put takes too long and effects small packet
* throughput, so unsplit small packets and save the alloc/put*/
- if (l1 && ((length + l1) < E1000_CB_LENGTH)) {
+ if (l1 && ((length + l1) <= adapter->rx_ps_bsize0)) {
u8 *vaddr;
/* there is no documentation about how to call
* kmap_atomic, so we can't hold the mapping