From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maciej Sosnowski Subject: [PATCH 5/7] I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3 Date: Thu, 26 Feb 2009 11:05:17 +0100 Message-ID: <20090226100515.3615.70407.stgit@linux.site> References: <20090226100327.3615.21419.stgit@linux.site> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: snakebyte@gmx.de, shannon.nelson@intel.com, jeffrey.t.krisher@intel.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: dan.j.williams@intel.com Return-path: Received: from mga01.intel.com ([192.55.52.88]:57832 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755495AbZBZKOA (ORCPT ); Thu, 26 Feb 2009 05:14:00 -0500 In-Reply-To: <20090226100327.3615.21419.stgit@linux.site> Sender: netdev-owner@vger.kernel.org List-ID: 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 Signed-off-by: Shannon Nelson Acked-by: Jeff Kirsher --- 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 }