[netdrvr] sfc: Add TSO support
The SFC4000 controller does not have hardware support for TSO, and the
core GSO code incurs a high cost in allocating and freeing skbs. This
TSO implementation uses lightweight packet header structures and is
substantially faster.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index c505482..6ffa711 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -134,6 +134,8 @@
* Set only on the final fragment of a packet; %NULL for all other
* fragments. When this fragment completes, then we can free this
* skb.
+ * @tsoh: The associated TSO header structure, or %NULL if this
+ * buffer is not a TSO header.
* @dma_addr: DMA address of the fragment.
* @len: Length of this fragment.
* This field is zero when the queue slot is empty.
@@ -144,6 +146,7 @@
*/
struct efx_tx_buffer {
const struct sk_buff *skb;
+ struct efx_tso_header *tsoh;
dma_addr_t dma_addr;
unsigned short len;
unsigned char continuation;
@@ -187,6 +190,13 @@
* variable indicates that the queue is full. This is to
* avoid cache-line ping-pong between the xmit path and the
* completion path.
+ * @tso_headers_free: A list of TSO headers allocated for this TX queue
+ * that are not in use, and so available for new TSO sends. The list
+ * is protected by the TX queue lock.
+ * @tso_bursts: Number of times TSO xmit invoked by kernel
+ * @tso_long_headers: Number of packets with headers too long for standard
+ * blocks
+ * @tso_packets: Number of packets via the TSO xmit path
*/
struct efx_tx_queue {
/* Members which don't change on the fast path */
@@ -206,6 +216,10 @@
unsigned int insert_count ____cacheline_aligned_in_smp;
unsigned int write_count;
unsigned int old_read_count;
+ struct efx_tso_header *tso_headers_free;
+ unsigned int tso_bursts;
+ unsigned int tso_long_headers;
+ unsigned int tso_packets;
};
/**
