From owner-freebsd-net Thu Aug 3 6: 8: 5 2000 Delivered-To: freebsd-net@freebsd.org Received: from info.iet.unipi.it (info.iet.unipi.it [131.114.9.184]) by hub.freebsd.org (Postfix) with ESMTP id EEF6B37B80A for ; Thu, 3 Aug 2000 06:07:42 -0700 (PDT) (envelope-from luigi@info.iet.unipi.it) Received: (from luigi@localhost) by info.iet.unipi.it (8.9.3/8.9.3) id PAA22493; Thu, 3 Aug 2000 15:05:35 +0200 (CEST) (envelope-from luigi) From: Luigi Rizzo Message-Id: <200008031305.PAA22493@info.iet.unipi.it> Subject: Re: Max data queued for UDP In-Reply-To: <200008030001.RAA28226@bubba.whistle.com> from Archie Cobbs at "Aug 2, 2000 05:01:16 pm" To: Archie Cobbs Date: Thu, 3 Aug 2000 15:05:35 +0200 (CEST) Cc: jayanth , freebsd-net@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL61 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > One of the issues is that the driver uses a cluster for > > every data packet, however small the data packet is. ... > When you say "the driver uses a cluster for every data packet, > however small the data packet is" are you referring to a specific > Ethernet driver? If so then that driver is lame. It should at > least have two possibilities: (a) normal mbuf, and (b) cluster. > It's very easy and fast to make that minimal decision. not so fast. Some NICs (especially fast ones) DMA directly into memory, and so the obvious choice is to put clusters in the receive ring buffer. The NIC normally cannot be instructed to use either of them. What you can do (maybe) is to decide to copy back small packets into the mbuf and free the cluster, as someone else suggested. cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) Mobile +39-347-0373137 -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message