From: Anton Blanchard <anton@samba•org>
To: brking@linux•vnet.ibm.com, santil@linux•vnet.ibm.com
Cc: netdev@vger•kernel.org
Subject: [patch 04/20] ibmveth: Add tx_copybreak
Date: Mon, 23 Aug 2010 10:09:34 +1000 [thread overview]
Message-ID: <20100823001238.661834862@samba.org> (raw)
In-Reply-To: 20100823000930.546065833@samba.org
[-- Attachment #1: veth_tx_copybreak --]
[-- Type: text/plain, Size: 2038 bytes --]
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>
---
Index: net-next-2.6/drivers/net/ibmveth.c
===================================================================
--- net-next-2.6.orig/drivers/net/ibmveth.c 2010-08-23 08:52:28.563877123 +1000
+++ net-next-2.6/drivers/net/ibmveth.c 2010-08-23 08:52:29.173833820 +1000
@@ -117,6 +117,11 @@ MODULE_DESCRIPTION("IBM i/pSeries Virtua
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(st
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;
next prev parent reply other threads:[~2010-08-23 0:27 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-23 0:09 [patch 00/20] ibmveth update Anton Blanchard
2010-08-23 0:09 ` [patch 01/20] ibmveth: Remove integer divide caused by modulus Anton Blanchard
2010-08-23 0:09 ` [patch 02/20] ibmveth: batch rx buffer replacement Anton Blanchard
2010-08-23 0:09 ` [patch 03/20] ibmveth: Remove LLTX Anton Blanchard
2010-08-23 0:09 ` Anton Blanchard [this message]
2010-08-23 0:09 ` [patch 05/20] ibmveth: Add rx_copybreak Anton Blanchard
2010-08-23 0:09 ` [patch 06/20] ibmveth: Use lighter weight read memory barrier in ibmveth_poll Anton Blanchard
2010-08-23 0:09 ` [patch 07/20] ibmveth: Add scatter-gather support Anton Blanchard
2010-08-23 0:09 ` [patch 08/20] ibmveth: Dont overallocate buffers Anton Blanchard
2010-08-23 20:49 ` Robert Jennings
2010-08-25 13:44 ` Brian King
2010-08-23 0:09 ` [patch 09/20] ibmveth: Add optional flush of rx buffer Anton Blanchard
2010-08-23 0:09 ` [patch 10/20] ibmveth: remove procfs code Anton Blanchard
2010-08-23 0:09 ` [patch 11/20] ibmveth: Convert to netdev_alloc_skb Anton Blanchard
2010-08-23 0:09 ` [patch 12/20] ibmveth: Remove redundant function prototypes Anton Blanchard
2010-08-23 0:09 ` [patch 13/20] ibmveth: Convert driver specific debug to netdev_dbg Anton Blanchard
2010-08-23 0:09 ` [patch 14/20] ibmveth: Convert driver specific error functions to netdev_err Anton Blanchard
2010-08-23 0:09 ` [patch 15/20] ibmveth: Some formatting fixes Anton Blanchard
2010-08-23 0:09 ` [patch 16/20] ibmveth: Coding style fixes Anton Blanchard
2010-08-23 0:09 ` [patch 17/20] ibmveth: Return -EINVAL on all ->probe errors Anton Blanchard
2010-08-23 0:09 ` [patch 18/20] ibmveth: Convert driver specific assert to BUG_ON Anton Blanchard
2010-08-23 0:09 ` [patch 19/20] ibmveth: Remove some unnecessary include files Anton Blanchard
2010-08-23 0:09 ` [patch 20/20] ibmveth: Update module information and version Anton Blanchard
2010-08-23 1:57 ` [patch 00/20] ibmveth update David Miller
2010-08-23 2:07 ` Anton Blanchard
2010-08-23 2:15 ` David Miller
[not found] <20100819072456.317416634@samba.org>
[not found] ` <20100819072503.937364037@samba.org>
2010-08-19 13:34 ` [patch 04/20] ibmveth: Add tx_copybreak Brian King
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