Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932287AbVIYU7k (ORCPT ); Sun, 25 Sep 2005 16:59:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932290AbVIYU7k (ORCPT ); Sun, 25 Sep 2005 16:59:40 -0400 Received: from 213-239-205-147.clients.your-server.de ([213.239.205.147]:11167 "EHLO mail.tglx.de") by vger.kernel.org with ESMTP id S932287AbVIYU7j (ORCPT ); Sun, 25 Sep 2005 16:59:39 -0400 Subject: Re: [ANNOUNCE] ktimers subsystem From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Roman Zippel Cc: Ingo Molnar , Christopher Friesen , linux-kernel@vger.kernel.org, akpm@osdl.org, george@mvista.com, johnstul@us.ibm.com, paulmck@us.ibm.com In-Reply-To: References: <20050919184834.1.patchmail@tglx.tec.linutronix.de> <1127342485.24044.600.camel@tglx.tec.linutronix.de> <43333EBA.5030506@nortel.com> <1127458197.24044.726.camel@tglx.tec.linutronix.de> <20050924051643.GB29052@elte.hu> <1127570212.15115.77.camel@tglx.tec.linutronix.de> Content-Type: text/plain Organization: linutronix Date: Sun, 25 Sep 2005 23:00:05 +0200 Message-Id: <1127682006.15115.96.camel@tglx.tec.linutronix.de> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 981 Lines: 23 On Sun, 2005-09-25 at 01:45 +0200, Roman Zippel wrote: > > The backward conversion from nsec_t to timespec is almost a non issue. > > The vast majority of callers dont provide the second argument to > > nanosleep(), setitimer(), set_timer() which makes the conversion > > necessary and I think we optimize for the common use case. > > You know very well, that the conversion back to timespec is the killer in > your calculation. You graciously decide that the "vast majority" doesn't > want to read the timer, how did you get to that conclusion? I graciously put instrumentation into _all_ the relevant syscalls on a desktop and a server machine. The result is that less than 1% of the calls provide the read back variable. tglx - 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/