From owner-freebsd-stable@FreeBSD.ORG Tue Sep 25 13:28:46 2007 Return-Path: Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CB44316A418 for ; Tue, 25 Sep 2007 13:28:46 +0000 (UTC) (envelope-from matrix@itlegion.ru) Received: from corpmail.itlegion.ru (corpmail.itlegion.ru [84.21.226.211]) by mx1.freebsd.org (Postfix) with SMTP id E32CD13C4A8 for ; Tue, 25 Sep 2007 13:28:45 +0000 (UTC) (envelope-from matrix@itlegion.ru) Received: (qmail 7323 invoked from network); 25 Sep 2007 17:28:43 +0400 Received: from unknown (HELO Artem) (192.168.0.12) by 84.21.226.211 with SMTP; 25 Sep 2007 17:28:43 +0400 X-AntiVirus: Checked by Dr.Web [version: 4.33, engine: 4.33.5.10110, virus records: 254484, updated: 25.09.2007] Message-ID: <022e01c7ff77$fc68b4a0$0c00a8c0@Artem> From: "Artem Kuchin" To: , References: <200709251257.l8PCvuZ8001535@lurza.secnetix.de> Date: Tue, 25 Sep 2007 17:28:37 +0400 Organization: IT Legion MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="ISO-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 Cc: Subject: Re: device polling and weird timer interrupt count from vmstat X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Sep 2007 13:28:46 -0000 >> 3) Is timer int really generated on each cpu? Am i really wasting cpu >> time on ~4000 ints per second? > > 4000 ints per second is rather nothing on any modern CPU. > Have a look at the top(1) display of an otherwise idle > system. The "%interrupt" column should be zero, even if > it's processing 4000 timer interrupts per second. As far > as I know, the cpu timer interrupt handler is very light- > weight. Thank you for the answer. My convern is that with 4 CPUs i get 8000 ints/second. While em generates only about 200 ints/second. As i undertand not all int handlers are the same. Some are heavy and some are light on CPU. So, the question is what is better (better=less CPU time): 8000 ints/sec from timer or 200 ints/sec from NIC? -- Regards, Artem