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Commit 06917f75 authored by Dave Jiang's avatar Dave Jiang Committed by Jon Mason
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NTB: Improve performance with write combining 



Changing the memory window BAR mappings to write combining significantly
boosts the performance.  We will also use memcpy that uses non-temporal
store, which showed performance improvement when doing non-cached
memcpys.

Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarJon Mason <jdmason@kudzu.us>
parent 0e041fb5

drivers/ntb/ntb_transport.c

+10 −1
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#include <linux/pci.h>

#include <linux/slab.h>

#include <linux/types.h>

#include <linux/uaccess.h>

#include "linux/ntb.h"

#include "linux/ntb_transport.h"
@@ -993,7 +994,7 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev) 
		if (rc)

			goto err1;



		mw->vbase = ioremap(mw->phys_addr, mw->phys_size);

		mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);

		if (!mw->vbase) {

			rc = -ENOMEM;

			goto err1;
@@ -1375,7 +1376,15 @@ static void ntb_tx_copy_callback(void *data) 


static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)

{

#ifdef ARCH_HAS_NOCACHE_UACCESS

	/*

	 * Using non-temporal mov to improve performance on non-cached

	 * writes, even though we aren't actually copying from user space.

	 */

	__copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);

#else

	memcpy_toio(offset, entry->buf, entry->len);

#endif



	/* Ensure that the data is fully copied out before setting the flags */

	wmb();