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I/OAT: tcp_dma_copybreak default value dependent on I/OAT version 

I/OAT DMA performance tuning showed different optimal values of
tcp_dma_copybreak for different I/OAT versions (4096 for 1.2 and 2048
for 2.0).  This patch lets ioatdma driver set tcp_dma_copybreak value
according to these results.

[dan.j.williams@intel.com: remove some ifdefs]
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Maciej Sosnowski 2008-07-22 17:30:57 -07:00 committed by Dan Williams
parent 09177e85d6
commit 16a37acaaf
3 changed files with 18 additions and 0 deletions
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2
drivers/dma/ioat_dma.c
View File

@ -1581,6 +1581,8 @@ struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
if (err)
goto err_self_test;
ioat_set_tcp_copy_break(device);
dma_async_device_register(&device->common);
INIT_DELAYED_WORK(&device->work, ioat_dma_chan_watchdog);

15
drivers/dma/ioatdma.h
View File

@ -27,6 +27,7 @@
#include <linux/dmapool.h>
#include <linux/cache.h>
#include <linux/pci_ids.h>
#include <net/tcp.h>
#define IOAT_DMA_VERSION "2.18"
@ -129,6 +130,20 @@ struct ioat_desc_sw {
struct dma_async_tx_descriptor async_tx;
};
static inline void ioat_set_tcp_copy_break(struct ioatdma_device *dev)
{
#ifdef CONFIG_NET_DMA
switch (dev->version) {
case IOAT_VER_1_2:
sysctl_tcp_dma_copybreak = 4096;
break;
case IOAT_VER_2_0:
sysctl_tcp_dma_copybreak = 2048;
break;
}
#endif
}
#if defined(CONFIG_INTEL_IOATDMA) || defined(CONFIG_INTEL_IOATDMA_MODULE)
struct ioatdma_device *ioat_dma_probe(struct pci_dev *pdev,
void __iomem *iobase);

1
net/core/user_dma.c
View File

@ -34,6 +34,7 @@
#define NET_DMA_DEFAULT_COPYBREAK 4096
int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
EXPORT_SYMBOL(sysctl_tcp_dma_copybreak);
/**
* dma_skb_copy_datagram_iovec - Copy a datagram to an iovec.