From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757807AbcHZAQl (ORCPT ); Thu, 25 Aug 2016 20:16:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59438 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756186AbcHZAQk (ORCPT ); Thu, 25 Aug 2016 20:16:40 -0400 Date: Thu, 25 Aug 2016 16:59:06 -0700 (PDT) Message-Id: <20160825.165906.1864272195425576421.davem@redhat.com> To: xander.huff@ni.com Cc: nicolas.ferre@atmel.com, netdev@vger.kernel.org, nathan.sullivan@ni.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net: macb: Increase DMA TX buffer size From: David Miller In-Reply-To: <1472077539-18033-1-git-send-email-xander.huff@ni.com> References: <1472077539-18033-1-git-send-email-xander.huff@ni.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 25 Aug 2016 23:59:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xander Huff Date: Wed, 24 Aug 2016 17:25:39 -0500 > From: Nathan Sullivan > > In recent testing with the RT patchset, we have seen cases where the > transmit ring can fill even with up to 200 txbds in the ring. Increase the > size of the DMA TX ring to avoid overruns. > > Signed-off-by: Xander Huff > Signed-off-by: Nathan Sullivan This is really a short term solution. While a larger TX ring may help RT, it's wasteful to have a ring that large on non-RT. Both uses are valid. Therefore what really needs to happen is to make this driver support changing the RX and TX ring sizes at runtime via ethtool just like pretty much every other driver. THanks.