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[netdrvr] sfc: Add TSO support

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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>
This commit is contained in:
Ben Hutchings
2008-05-07 12:51:12 +01:00
committed by Jeff Garzik
parent 48cfb14f8b
commit b9b39b625c
4 changed files with 708 additions and 1 deletions
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14
drivers/net/sfc/net_driver.h
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@ -134,6 +134,8 @@ struct efx_special_buffer {
* 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_special_buffer {
*/
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 @@ struct efx_tx_buffer {
* 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 @@ struct efx_tx_queue {
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;
};
/**