Subject: [PATCH 5/7] I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3

From: Maciej Sosnowski <[email-masked]>
Date: Thu, 26 Feb 2009 11:05:17 +0100

Upcoming server platforms from Intel based on the Nehalem performance
have significantly improved CPU based copy performance.
However, the DMA engine can still be effective at higher I/O sizes
for TCP traffic and at this time copybreak
should be set to 256k for TCP traffic only.

Signed-off-by: Maciej Sosnowski <[email-masked]>
Signed-off-by: Shannon Nelson <[email-masked]>
Acked-by: Jeff Kirsher <[email-masked]>
---

 drivers/dma/ioatdma.h |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h
index a3306d0..dcf8db5 100644
--- a/drivers/dma/ioatdma.h
+++ b/drivers/dma/ioatdma.h
@@ -135,12 +135,14 @@ static inline void ioat_set_tcp_copy_bre
 	#ifdef CONFIG_NET_DMA
 	switch (dev->version) {
 	case IOAT_VER_1_2:
-	case IOAT_VER_3_0:
 		sysctl_tcp_dma_copybreak = 4096;
 		break;
 	case IOAT_VER_2_0:
 		sysctl_tcp_dma_copybreak = 2048;
 		break;
+	case IOAT_VER_3_0:
+		sysctl_tcp_dma_copybreak = 262144;
+		break;
 	}
 	#endif
 }