This patchset enables TCP checksum offload support for IPV4
on ibmveth. This completely eliminates the generation and checking of
the checksum for packets that are completely virtual and never
touch a physical network. A simple TCP_STREAM netperf run on
a virtual network with maximum mtu set yielded a ~30% increase
in throughput. This feature is enabled by default on systems that
support it, but can be disabled with a module option.
Signed-off-by: Brian King <[EMAIL PROTECTED]>
---
linux-2.6-bjking1/drivers/net/ibmveth.c | 53 ++++++++++++++++++++++++++++++++
linux-2.6-bjking1/drivers/net/ibmveth.h | 41 +++++++++++++++++++++++-
2 files changed, 92 insertions(+), 2 deletions(-)
diff -puN drivers/net/ibmveth.c~ibmveth_csum_offload drivers/net/ibmveth.c
--- linux-2.6/drivers/net/ibmveth.c~ibmveth_csum_offload 2007-08-01
14:55:11.000000000 -0500
+++ linux-2.6-bjking1/drivers/net/ibmveth.c 2007-08-01 14:55:11.000000000
-0500
@@ -47,6 +47,8 @@
#include <linux/mm.h>
#include <linux/ethtool.h>
#include <linux/proc_fs.h>
+#include <linux/in.h>
+#include <linux/ip.h>
#include <asm/semaphore.h>
#include <asm/hvcall.h>
#include <asm/atomic.h>
@@ -131,6 +133,11 @@ static inline int ibmveth_rxq_frame_leng
return (adapter->rx_queue.queue_addr[adapter->rx_queue.index].length);
}
+static inline int ibmveth_rxq_csum_good(struct ibmveth_adapter *adapter)
+{
+ return
(adapter->rx_queue.queue_addr[adapter->rx_queue.index].csum_good);
+}
+
/* setup the initial settings for a buffer pool */
static void ibmveth_init_buffer_pool(struct ibmveth_buff_pool *pool, u32
pool_index, u32 pool_size, u32 buff_size, u32 pool_active)
{
@@ -684,6 +691,24 @@ static int ibmveth_start_xmit(struct sk_
desc[0].fields.length, DMA_TO_DEVICE);
desc[0].fields.valid = 1;
+ if (skb->ip_summed == CHECKSUM_PARTIAL &&
+ ip_hdr(skb)->protocol != IPPROTO_TCP && skb_checksum_help(skb)) {
+ ibmveth_error_printk("tx: failed to checksum packet\n");
+ tx_dropped++;
+ goto out;
+ }
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ unsigned char *buf = skb_transport_header(skb) +
skb->csum_offset;
+
+ desc[0].fields.no_csum = 1;
+ desc[0].fields.csum_good = 1;
+
+ /* Need to zero out the checksum */
+ buf[0] = 0;
+ buf[1] = 0;
+ }
+
if(dma_mapping_error(desc[0].fields.address)) {
ibmveth_error_printk("tx: unable to map initial fragment\n");
tx_map_failed++;
@@ -702,6 +727,10 @@ static int ibmveth_start_xmit(struct sk_
frag->size, DMA_TO_DEVICE);
desc[curfrag+1].fields.length = frag->size;
desc[curfrag+1].fields.valid = 1;
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ desc[curfrag+1].fields.no_csum = 1;
+ desc[curfrag+1].fields.csum_good = 1;
+ }
if(dma_mapping_error(desc[curfrag+1].fields.address)) {
ibmveth_error_printk("tx: unable to map fragment %d\n",
curfrag);
@@ -792,7 +821,11 @@ static int ibmveth_poll(struct net_devic
} else {
int length = ibmveth_rxq_frame_length(adapter);
int offset = ibmveth_rxq_frame_offset(adapter);
+ int csum_good = ibmveth_rxq_csum_good(adapter);
+
skb = ibmveth_rxq_get_buffer(adapter);
+ if (csum_good)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
ibmveth_rxq_harvest_buffer(adapter);
@@ -962,8 +995,10 @@ static void ibmveth_poll_controller(stru
static int __devinit ibmveth_probe(struct vio_dev *dev, const struct
vio_device_id *id)
{
int rc, i;
+ long ret;
struct net_device *netdev;
struct ibmveth_adapter *adapter = NULL;
+ union ibmveth_illan_attributes set_attr, ret_attr;
unsigned char *mac_addr_p;
unsigned int *mcastFilterSize_p;
@@ -1058,6 +1093,24 @@ static int __devinit ibmveth_probe(struc
ibmveth_debug_printk("registering netdev...\n");
+ ret = h_illan_attributes(dev->unit_address, 0, 0, &ret_attr.desc);
+
+ if (ret == H_SUCCESS && !ret_attr.fields.active_trunk &&
+ !ret_attr.fields.trunk_priority &&
+ ret_attr.fields.csum_offload_padded_pkt_support) {
+ set_attr.desc = 0;
+ set_attr.fields.tcp_csum_offload_ipv4 = 1;
+
+ ret = h_illan_attributes(dev->unit_address, 0, set_attr.desc,
+ &ret_attr.desc);
+
+ if (ret == H_SUCCESS)
+ netdev->features |= NETIF_F_IP_CSUM;
+ else
+ ret = h_illan_attributes(dev->unit_address,
set_attr.desc,
+ 0, &ret_attr.desc);
+ }
+
rc = register_netdev(netdev);
if(rc) {
diff -puN drivers/net/ibmveth.h~ibmveth_csum_offload drivers/net/ibmveth.h
--- linux-2.6/drivers/net/ibmveth.h~ibmveth_csum_offload 2007-08-01
14:55:11.000000000 -0500
+++ linux-2.6-bjking1/drivers/net/ibmveth.h 2007-08-01 14:55:11.000000000
-0500
@@ -67,6 +67,21 @@ static inline long h_send_logical_lan(un
return rc;
}
+static inline long h_illan_attributes(unsigned long unit_address,
+ unsigned long reset_mask, unsigned long
set_mask,
+ unsigned long *ret_attributes)
+{
+ long rc;
+ unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+ rc = plpar_hcall(H_ILLAN_ATTRIBUTES, retbuf, unit_address,
+ reset_mask, set_mask);
+
+ *ret_attributes = retbuf[0];
+
+ return rc;
+}
+
#define h_multicast_ctrl(ua, cmd, mac) \
plpar_hcall_norets(H_MULTICAST_CTRL, ua, cmd, mac)
@@ -141,7 +156,9 @@ struct ibmveth_adapter {
struct ibmveth_buf_desc_fields {
u32 valid : 1;
u32 toggle : 1;
- u32 reserved : 6;
+ u32 reserved : 4;
+ u32 no_csum : 1;
+ u32 csum_good : 1;
u32 length : 24;
u32 address;
};
@@ -151,10 +168,30 @@ union ibmveth_buf_desc {
struct ibmveth_buf_desc_fields fields;
};
+struct ibmveth_illan_attributes_fields {
+ u32 reserved;
+ u32 reserved2 : 18;
+ u32 csum_offload_padded_pkt_support : 1;
+ u32 reserved3 : 1;
+ u32 trunk_priority : 4;
+ u32 reserved4 : 5;
+ u32 tcp_csum_offload_ipv6 : 1;
+ u32 tcp_csum_offload_ipv4 : 1;
+ u32 active_trunk : 1;
+};
+
+union ibmveth_illan_attributes {
+ u64 desc;
+ struct ibmveth_illan_attributes_fields fields;
+};
+
struct ibmveth_rx_q_entry {
u16 toggle : 1;
u16 valid : 1;
- u16 reserved : 14;
+ u16 reserved : 4;
+ u16 no_csum : 1;
+ u16 csum_good : 1;
+ u16 reserved2 : 8;
u16 offset;
u32 length;
u64 correlator;
_
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