From owner-freebsd-net@FreeBSD.ORG Tue Jul 27 11:52:03 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 057D016A4CE for ; Tue, 27 Jul 2004 11:52:03 +0000 (GMT) Received: from jagor.srce.hr (jagor.srce.hr [161.53.2.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id AFA8643D54 for ; Tue, 27 Jul 2004 11:52:01 +0000 (GMT) (envelope-from zec@tel.fer.hr) Received: from [192.168.232.142] (cmung5528.cmu.carnet.hr [193.198.149.194]) by jagor.srce.hr (8.12.10/8.12.10) with ESMTP id i6RBpvm9016918; Tue, 27 Jul 2004 13:51:58 +0200 (CEST) From: Marko Zec To: "'James'" Date: Tue, 27 Jul 2004 13:36:34 +0200 User-Agent: KMail/1.6.2 References: In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200407271336.34744.zec@tel.fer.hr> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.42 X-Virus-Scanned: by amavisd-new at jagor.srce.hr cc: freebsd-net@freebsd.org Subject: Re: device polling takes more CPU hits?? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Jul 2004 11:52:03 -0000 James, what timecounter method are you using, i8254 or TSC? The polling code frequently calls microuptime(), which is very expensive (slow) with i8254, while being reasonable fast with TSC. Since you are running with quite high system clock (4 kHz), using i8254 could be causing the problems you've described. Cheers, Marko On Monday 26 July 2004 22:27, Don Bowman wrote: > From: James [mailto:haesu@towardex.com] > > > I have two boxes behind em0 that I can use to generate > > 250kpps to another vlan > > within em0 card as a test, so that bge0 is not involved in > > the stress test. > > Even when doing so, CPU load climbs higher with device > > polling turned on. > > Opened up systat, etc to check the interrupts, and em0 is > > generating 0 > > interrupts with device polling on (as obvious), but general > > interrupt load > > climbs rock high.. so I don't know what's causing it to > > climb. Cleared the > > firewall rules as well as a test... no difference :( > > > > Oh also, just FYI, each vlan interface has link0 set, since > > em(4) supports > > hardware 802.1q tag/detagging. > > The CPU time during the 'polling' is charged to interrupt, > even though it occurs during softclock. That's why you > see 0 interrupts, but high CPU usage in interrupt. > Did u try lowering the 'register' access? > > --don