From owner-freebsd-hardware@FreeBSD.ORG Tue Sep 4 19:13:01 2012 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 276EE106566B for ; Tue, 4 Sep 2012 19:13:01 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigknife-pt.tunnel.tserv9.chi1.ipv6.he.net [IPv6:2001:470:1f10:75::2]) by mx1.freebsd.org (Postfix) with ESMTP id F221B8FC1D for ; Tue, 4 Sep 2012 19:13:00 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 46CC4B999; Tue, 4 Sep 2012 15:13:00 -0400 (EDT) From: John Baldwin To: freebsd-hardware@freebsd.org Date: Tue, 4 Sep 2012 12:13:10 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p17; KDE/4.5.5; amd64; ; ) References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201209041213.10931.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Tue, 04 Sep 2012 15:13:00 -0400 (EDT) Cc: Andy Young Subject: Re: What is rx_processing_limit sysctl for Intel igb NIC driver? X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Sep 2012 19:13:01 -0000 On Sunday, September 02, 2012 10:41:15 pm Andy Young wrote: > I am tuning our server that has an Intel 82576 gigabit NIC using the igb > driver. I see a lot of posts on the net where people bump the > rx_processing_limit sysctl from the default value of 100 to 4096. Can > anyone tell me what this is intended to do? If you have multiple devices sharing an IRQ with igb (and thus are not using MSI or MSI-X), it forces the driver to more-or-less cooperatively schedule with the other interrupts on the same IRQ. However, since igb uses a fast interrupt handler and a task on a dedicated taskqueue in the non-MSI case now, I think it doesn't even do that. It should probably be set to -1 (meaning unlimited) in just about all cases now. -- John Baldwin