From: Maciej Sosnowski <maciej.sosnowski@intel.com>
Date: Thu, 26 Feb 2009 10:05:17 +0000 (+0100)
Subject: I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=5de22343b2303b278ab562e5d166ffe306566d30;p=linux-2.6-omap-h63xx.git

I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3

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 <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---

diff --git a/drivers/dma/ioatdma.h b/drivers/dma/ioatdma.h
index a3306d0e137..dcf8db513c3 100644
--- a/drivers/dma/ioatdma.h
+++ b/drivers/dma/ioatdma.h
@@ -135,12 +135,14 @@ static inline void ioat_set_tcp_copy_break(struct ioatdma_device *dev)
 	#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
 }