From owner-freebsd-hackers@FreeBSD.ORG Thu Jul 25 20:31:55 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 326FE6F2; Thu, 25 Jul 2013 20:31:55 +0000 (UTC) (envelope-from superbisquit@gmail.com) Received: from mail-oa0-x231.google.com (mail-oa0-x231.google.com [IPv6:2607:f8b0:4003:c02::231]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id C3EFA2E64; Thu, 25 Jul 2013 20:31:54 +0000 (UTC) Received: by mail-oa0-f49.google.com with SMTP id n12so5499057oag.36 for ; Thu, 25 Jul 2013 13:31:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=MWXqU+js3bXhIe/rtkwsupkW59SZPsfz2LuMMeYKeTs=; b=qSmbQWpn41VlKDsHvI9XN3X0O/twhX5lmqx22ipULqUNvahKpzTUC8wLuJG1meRXDL z9Hn1iv3E6T2Lxv/HJEIx6lgM32m0znBVclEk9QcnNcbMvdoHHz3K9wuAEGi1cbVNrpO TTl9SRBGEDrM/dmw/HSRYt4835XIK19Jmhbqi6nUFwLMdDXsYcCOInYt7UGOc6Tis0gd WvLFQ4Adga8/HfqTM1v98iq+yDk0UPR3M61kW6UzDxJthLS+fUzpCfi8k129VberpJah kjt5mMMBul54WsjaD0zQd23imL0jWTsuudvBdvfc7LVFB5trZlDYKsZm66mxB6wLxVcl Swxg== MIME-Version: 1.0 X-Received: by 10.60.52.78 with SMTP id r14mr45103404oeo.9.1374784314010; Thu, 25 Jul 2013 13:31:54 -0700 (PDT) Received: by 10.182.115.194 with HTTP; Thu, 25 Jul 2013 13:31:53 -0700 (PDT) In-Reply-To: References: Date: Thu, 25 Jul 2013 16:31:53 -0400 Message-ID: Subject: Re: Kern.hz= +1 hertz at anything 2500 and above. From: Super Bisquit To: Adrian Chadd Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: Wojciech Puchar , freebsd-current , FreeBSD Hackers , FreeBSD PowerPC ML X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Jul 2013 20:31:55 -0000 I haven't done much messing with scheduling. It is set at the default ULE for this machine. On Thu, Jul 25, 2013 at 12:11 PM, Adrian Chadd wrote: > On 25 July 2013 02:51, Wojciech Puchar > wrote: > >> improved with a higher kern.hz rating. Unless the future holds an > emu20k2, > >> there will be RAM used from the motherboard. > >> 1. I will need a real-time or a faster kernel- hence the high rate > wanted- > >> because the devices to be built will be used in an active environment: > >> art, > >> music, audio control. > >> 2. Any system with limited memory and a low CPU hertz rate benefits from > >> the higher kern.hz setting. > > > rather opposite. more kern.hz=more interrupts. > > Right. > > More hz == more interrupts and less ability for a CPU-bound process to > chew all the CPU. > > So is it a scheduling issue, where you have multiple CPU bound > userland processes that aren't being fair and consuming all the CPU? > Is it that your device driver(s) aren't interrupting correctly, > relying on the hz tick to make up the slack, etc. > > Is it a busted halt loop, which is being papered over with hz ticks? > > Have you tried -10 on that kit, with the more aggressive clock/timer > code that won't interrupt unless it needs to? Has that changed things? > > > > -adrian >