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

Message ID 20090226100515.3615.70407.stgit@linux.site
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

Sosnowski, Maciej Feb. 26, 2009, 10:05 a.m.
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.krisher@intel.com>

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

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html


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
 	switch (dev->version) {
 	case IOAT_VER_1_2:
-	case IOAT_VER_3_0:
 		sysctl_tcp_dma_copybreak = 4096;
 	case IOAT_VER_2_0:
 		sysctl_tcp_dma_copybreak = 2048;
+	case IOAT_VER_3_0:
+		sysctl_tcp_dma_copybreak = 262144;
+		break;