Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 27 Jun 2002 17:06:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 27 Jun 2002 17:06:21 -0400 Received: from quechua.inka.de ([212.227.14.2]:21583 "EHLO mail.inka.de") by vger.kernel.org with ESMTP id ; Thu, 27 Jun 2002 17:06:20 -0400 From: Bernd Eckenfels To: linux-kernel@vger.kernel.org Subject: Re: zero-copy networking & a performance drop In-Reply-To: X-Newsgroups: ka.lists.linux.kernel User-Agent: tin/1.5.8-20010221 ("Blue Water") (UNIX) (Linux/2.0.39 (i686)) Message-Id: Date: Thu, 27 Jun 2002 23:08:40 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1188 Lines: 24 In article you wrote: > Previous tests have show that we can transmit IP packets easily at around > 1.4 Gbit, but we can only receive at about 0.9 Gbit. We suspect there is a > memory copy somewhere either in the quadrics IP driver (covered by an NDA, > sorry), or in the IP stack after netif_rx() is called. I've looked at the > driver, and, upon a (good) cursory inspection, it looks good. You have to sign a NDA for a hardware which bahaves slower than expected and then u seek help in the open community? I would ask you to bother the manufacturer, so they know about this problem and solve it. After all, if you have to pay for it you should actually USE their service. AFAIK only a few methods like sendfile support zero copy ip. But on the other hand, if the card works by memory sharing perhaps TCP/IP is simply the wrong api to speak to that device? Greetings Bernd - 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/