Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262622AbUK0CxQ (ORCPT ); Fri, 26 Nov 2004 21:53:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263048AbUK0CEn (ORCPT ); Fri, 26 Nov 2004 21:04:43 -0500 Received: from zeus.kernel.org ([204.152.189.113]:10692 "EHLO zeus.kernel.org") by vger.kernel.org with ESMTP id S262995AbUKZTiP (ORCPT ); Fri, 26 Nov 2004 14:38:15 -0500 From: Robert Olsson MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16806.1163.601015.670054@robur.slu.se> Date: Thu, 25 Nov 2004 17:12:59 +0100 To: Justin Piszcz Cc: linux-kernel@vger.kernel.org, Robert.Olsson@data.slu.se Subject: CONFIG_TULIP_NAPI_HW_MITIGATION latency question. In-Reply-To: References: X-Mailer: VM 7.18 under Emacs 21.3.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1019 Lines: 35 Justin Piszcz writes: > "at the cost of a small latency" > > How much additional latency is added with this option enabled? > > 5ms? 10ms? > > -> Use Interrupt Mitigation > x CONFIG_TULIP_NAPI_HW_MITIGATION: > x Use HW to reduce RX interrupts. Not strict necessary since NAPI > reduces RX interrupts but itself. Although this reduces RX interrupts even at > low levels traffic at the cost of a small latency. > x > x If in doubt, say Y. Hello! It's in usec and the tulip only enables this latency when it's needed it really tries to keep latency down. It has three steeps of input control. Low rate: No driver latency. No interrupt delay at all. Medium rate: Samll driver latency. High rate: Polling via ->poll --ro - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/