Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261507AbVETQ6b (ORCPT ); Fri, 20 May 2005 12:58:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261502AbVETQ6a (ORCPT ); Fri, 20 May 2005 12:58:30 -0400 Received: from ns1.lanforge.com ([66.165.47.210]:2016 "EHLO www.lanforge.com") by vger.kernel.org with ESMTP id S261498AbVETQ6G (ORCPT ); Fri, 20 May 2005 12:58:06 -0400 Message-ID: <428E16D1.2070800@candelatech.com> Date: Fri, 20 May 2005 09:56:49 -0700 From: Ben Greear Organization: Candela Technologies User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.7.7) Gecko/20050417 Fedora/1.7.7-1.3.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Lee Revell CC: Helge Hafting , Arjan van de Ven , linux-os@analogic.com, Adrian Bunk , Kyle Moffett , "Gilbert, John" , linux-kernel@vger.kernel.org Subject: Re: Illegal use of reserved word in system.h References: <2692A548B75777458914AC89297DD7DA08B0866F@bronze.dolby.net> <20050518195337.GX5112@stusta.de> <6EA08D88-7C67-48ED-A9EF-FEAAB92D8B8F@mac.com> <20050519112840.GE5112@stusta.de> <1116505655.6027.45.camel@laptopd505.fenrus.org> <428CCD19.6030909@candelatech.com> <428DAD71.4050105@aitel.hist.no> <1116607623.28552.12.camel@mindpipe> In-Reply-To: <1116607623.28552.12.camel@mindpipe> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1432 Lines: 44 Lee Revell wrote: > On Fri, 2005-05-20 at 11:27 +0200, Helge Hafting wrote: > >>Ben Greear wrote: >> >> >>>Arjan van de Ven wrote: >>> >>> >>>>HZ may not exist. At all; people are trying to remove it. And userspace >>>>has no business knowing about it either. >>> >>> >>>It can be helpful to know what HZ you are running at, for instance if >>>you care >>>very much about the (average) precision of a select/poll timeout. >>> >> >>Will knowing it help? You may find out that you don't have much precision, >>but then theres nothing to do about it. > > > Yes, it will. If you have an RT constraint and 10ms won't cut it (say, > you want to send MIDI clock) then you can use the RTC. Right. For instance, before I found the 1000 HZ patch for the 2.4 kernel I would set the RTC to tick 1024 times a second, and then add that FD to my select() fd-sets. That causes select to return after about 1ms, and I could do this in a loop to get the X ms of sleep that I needed. This is not as nice as having a clean 1ms tick clock, but it's a hell of a lot better than a full busy spin... Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/