pasemi_mac: further performance tweaks
pasemi_mac: further performance tweaks Misc driver tweaks for pasemi_mac: * Increase ring size (really needed mostly on 10G) * Take out an unneeded barrier * Move around a few prefetches and reorder a few calls * Don't try to clean on full tx buffer, just let things take their course and stop the queue directly * Avoid filling on the same line as the interface is working on to reduce cache line bouncing * Avoid unneeded clearing of software state (and make the interface shutdown code handle it) * Fix up some of the tx ring wrap logic. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Olof Johansson
David S. Miller
parent
8dc121a4b6
commit
ad5da10a64
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@ -56,8 +56,8 @@
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/* Must be a power of two */
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#define RX_RING_SIZE 512
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#define TX_RING_SIZE 512
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#define RX_RING_SIZE 4096
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#define TX_RING_SIZE 4096
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#define DEFAULT_MSG_ENABLE \
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(NETIF_MSG_DRV | \
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@ -336,8 +336,16 @@ static void pasemi_mac_free_tx_resources(struct net_device *dev)
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struct pasemi_mac_buffer *info;
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dma_addr_t dmas[MAX_SKB_FRAGS+1];
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int freed;
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int start, limit;
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for (i = 0; i < TX_RING_SIZE; i += freed) {
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start = mac->tx->next_to_clean;
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limit = mac->tx->next_to_fill;
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/* Compensate for when fill has wrapped and clean has not */
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if (start > limit)
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limit += TX_RING_SIZE;
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for (i = start; i < limit; i += freed) {
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info = &TX_RING_INFO(mac, i+1);
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if (info->dma && info->skb) {
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for (j = 0; j <= skb_shinfo(info->skb)->nr_frags; j++)
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@ -520,9 +528,6 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
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n = mac->rx->next_to_clean;
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for (count = limit; count; count--) {
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rmb();
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macrx = RX_RING(mac, n);
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if ((macrx & XCT_MACRX_E) ||
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@ -550,14 +555,10 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
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break;
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}
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prefetchw(info);
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skb = info->skb;
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prefetchw(skb);
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info->dma = 0;
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pci_unmap_single(mac->dma_pdev, dma, skb->len,
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PCI_DMA_FROMDEVICE);
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prefetch(skb);
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prefetch(&skb->data_len);
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len = (macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;
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@ -576,10 +577,9 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
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} else
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info->skb = NULL;
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/* Need to zero it out since hardware doesn't, since the
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* replenish loop uses it to tell when it's done.
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*/
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RX_BUFF(mac, i) = 0;
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pci_unmap_single(mac->dma_pdev, dma, len, PCI_DMA_FROMDEVICE);
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info->dma = 0;
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skb_put(skb, len);
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@ -599,6 +599,11 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
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RX_RING(mac, n) = 0;
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RX_RING(mac, n+1) = 0;
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/* Need to zero it out since hardware doesn't, since the
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* replenish loop uses it to tell when it's done.
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*/
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RX_BUFF(mac, i) = 0;
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n += 2;
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}
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@ -621,27 +626,33 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
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static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
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{
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int i, j;
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struct pasemi_mac_buffer *info;
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unsigned int start, descr_count, buf_count, limit;
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unsigned int start, descr_count, buf_count, batch_limit;
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unsigned int ring_limit;
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unsigned int total_count;
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unsigned long flags;
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struct sk_buff *skbs[TX_CLEAN_BATCHSIZE];
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dma_addr_t dmas[TX_CLEAN_BATCHSIZE][MAX_SKB_FRAGS+1];
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total_count = 0;
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limit = TX_CLEAN_BATCHSIZE;
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batch_limit = TX_CLEAN_BATCHSIZE;
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restart:
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spin_lock_irqsave(&mac->tx->lock, flags);
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start = mac->tx->next_to_clean;
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ring_limit = mac->tx->next_to_fill;
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/* Compensate for when fill has wrapped but clean has not */
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if (start > ring_limit)
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ring_limit += TX_RING_SIZE;
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buf_count = 0;
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descr_count = 0;
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for (i = start;
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descr_count < limit && i < mac->tx->next_to_fill;
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descr_count < batch_limit && i < ring_limit;
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i += buf_count) {
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u64 mactx = TX_RING(mac, i);
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struct sk_buff *skb;
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if ((mactx & XCT_MACTX_E) ||
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(*mac->tx_status & PAS_STATUS_ERROR))
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@ -651,19 +662,15 @@ restart:
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/* Not yet transmitted */
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break;
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info = &TX_RING_INFO(mac, i+1);
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skbs[descr_count] = info->skb;
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skb = TX_RING_INFO(mac, i+1).skb;
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skbs[descr_count] = skb;
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buf_count = 2 + skb_shinfo(info->skb)->nr_frags;
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for (j = 0; j <= skb_shinfo(info->skb)->nr_frags; j++)
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buf_count = 2 + skb_shinfo(skb)->nr_frags;
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for (j = 0; j <= skb_shinfo(skb)->nr_frags; j++)
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dmas[descr_count][j] = TX_RING_INFO(mac, i+1+j).dma;
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info->dma = 0;
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TX_RING(mac, i) = 0;
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TX_RING(mac, i+1) = 0;
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TX_RING_INFO(mac, i+1).skb = 0;
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TX_RING_INFO(mac, i+1).dma = 0;
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/* Since we always fill with an even number of entries, make
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* sure we skip any unused one at the end as well.
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@ -672,7 +679,7 @@ restart:
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buf_count++;
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descr_count++;
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}
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mac->tx->next_to_clean = i;
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mac->tx->next_to_clean = i & (TX_RING_SIZE-1);
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spin_unlock_irqrestore(&mac->tx->lock, flags);
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netif_wake_queue(mac->netdev);
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@ -683,7 +690,7 @@ restart:
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total_count += descr_count;
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/* If the batch was full, try to clean more */
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if (descr_count == limit)
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if (descr_count == batch_limit)
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goto restart;
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return total_count;
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@ -1106,19 +1113,14 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
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spin_lock_irqsave(&txring->lock, flags);
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if (RING_AVAIL(txring) <= nfrags+3) {
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spin_unlock_irqrestore(&txring->lock, flags);
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pasemi_mac_clean_tx(mac);
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pasemi_mac_restart_tx_intr(mac);
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spin_lock_irqsave(&txring->lock, flags);
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if (RING_AVAIL(txring) <= nfrags+3) {
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/* Still no room -- stop the queue and wait for tx
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* intr when there's room.
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*/
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netif_stop_queue(dev);
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goto out_err;
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}
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/* Avoid stepping on the same cache line that the DMA controller
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* is currently about to send, so leave at least 8 words available.
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* Total free space needed is mactx + fragments + 8
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*/
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if (RING_AVAIL(txring) < nfrags + 10) {
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/* no room -- stop the queue and wait for tx intr */
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netif_stop_queue(dev);
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goto out_err;
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}
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TX_RING(mac, txring->next_to_fill) = mactx;
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@ -1137,8 +1139,8 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
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if (nfrags & 1)
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nfrags++;
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txring->next_to_fill += nfrags + 1;
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txring->next_to_fill = (txring->next_to_fill + nfrags + 1) &
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(TX_RING_SIZE-1);
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dev->stats.tx_packets++;
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dev->stats.tx_bytes += skb->len;
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