diff options
| author | Santiago Leon <santil@linux.vnet.ibm.com> | 2010-09-03 20:28:20 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-07 03:20:33 +0200 |
| commit | c08cc3ccebd46dce44d13a8ce81d249e687eeb8a (patch) | |
| tree | 1e44318be42fbbef6c6cc224c9d4a2adafef4e98 /drivers/net | |
| parent | ibmveth: Remove LLTX (diff) | |
| download | linux-c08cc3ccebd46dce44d13a8ce81d249e687eeb8a.tar.xz linux-c08cc3ccebd46dce44d13a8ce81d249e687eeb8a.zip | |
ibmveth: Add tx_copybreak
Use the existing bounce buffer if we send a buffer under a certain size.
This saves the overhead of a TCE map/unmap.
I can't see any reason for the wmb() in the bounce buffer case, if we need
a barrier it will be before we call h_send_logical_lan but we have
nothing in the common case. Remove it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Santiago Leon <santil@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ibmveth.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c index 9d662dec21b0..fc6e2cf879c0 100644 --- a/drivers/net/ibmveth.c +++ b/drivers/net/ibmveth.c @@ -117,6 +117,11 @@ MODULE_DESCRIPTION("IBM i/pSeries Virtual Ethernet Driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(ibmveth_driver_version); +static unsigned int tx_copybreak __read_mostly = 128; +module_param(tx_copybreak, uint, 0644); +MODULE_PARM_DESC(tx_copybreak, + "Maximum size of packet that is copied to a new buffer on transmit"); + struct ibmveth_stat { char name[ETH_GSTRING_LEN]; int offset; @@ -931,17 +936,24 @@ static netdev_tx_t ibmveth_start_xmit(struct sk_buff *skb, buf[1] = 0; } - data_dma_addr = dma_map_single(&adapter->vdev->dev, skb->data, - skb->len, DMA_TO_DEVICE); - if (dma_mapping_error(&adapter->vdev->dev, data_dma_addr)) { - if (!firmware_has_feature(FW_FEATURE_CMO)) - ibmveth_error_printk("tx: unable to map xmit buffer\n"); + if (skb->len < tx_copybreak) { + used_bounce = 1; + } else { + data_dma_addr = dma_map_single(&adapter->vdev->dev, skb->data, + skb->len, DMA_TO_DEVICE); + if (dma_mapping_error(&adapter->vdev->dev, data_dma_addr)) { + if (!firmware_has_feature(FW_FEATURE_CMO)) + ibmveth_error_printk("tx: unable to map " + "xmit buffer\n"); + tx_map_failed++; + used_bounce = 1; + } + } + + if (used_bounce) { skb_copy_from_linear_data(skb, adapter->bounce_buffer, skb->len); desc.fields.address = adapter->bounce_buffer_dma; - tx_map_failed++; - used_bounce = 1; - wmb(); } else desc.fields.address = data_dma_addr; |