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Commit 16a37aca authored by Maciej Sosnowski's avatar Maciej Sosnowski Committed by Dan Williams
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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: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 09177e85

drivers/dma/ioat_dma.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

drivers/dma/ioatdma.h

+15 −0
Original line number Diff line number Diff line
@@ -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);

net/core/user_dma.c

+1 −0
Original line number Diff line number Diff line
@@ -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.