[PATCH 1/7] I/OAT: Push pending transactions to hardware more frequently

[Chris Leech <christopher.leech@intel.com>]

Every 20 descriptors turns out to be to few append commands with
newer/faster CPUs.  Pushing every 4 still cuts down on MMIO writes to an
acceptable level without letting the DMA engine run out of work.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
---

 drivers/dma/ioatdma.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index 0358419..f3b34b5 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(s
 	list_splice_init(&new_chain, ioat_chan->used_desc.prev);
 
 	ioat_chan->pending += desc_count;
-	if (ioat_chan->pending >= 20) {
+	if (ioat_chan->pending >= 4) {
 		append = 1;
 		ioat_chan->pending = 0;
 	}
@@ -818,7 +818,7 @@ static void __devexit ioat_remove(struct
 }
 
 /* MODULE API */
-MODULE_VERSION("1.7");
+MODULE_VERSION("1.9");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Intel Corporation");
 

-
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