From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1756958AbcIUMi7 (ORCPT <rfc822;w@1wt.eu>);
        Wed, 21 Sep 2016 08:38:59 -0400
Received: from Galois.linutronix.de ([146.0.238.70]:34404 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1753056AbcIUMi5 (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 21 Sep 2016 08:38:57 -0400
Date: Wed, 21 Sep 2016 14:36:23 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
cc: Baolin Wang <baolin.wang@linaro.org>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Ingo Molnar <mingo@redhat.com>, John Stultz <john.stultz@linaro.org>,
        Mark Brown <broonie@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        rtc-linux@googlegroups.com
Subject: Re: [PATCH 2/2] time: alarmtimer: Add the trcepoints for
 alarmtimer
In-Reply-To: <20160921083305.24524304@gandalf.local.home>
Message-ID: <alpine.DEB.2.20.1609211435050.5573@nanos>
References: <8c570c152c95087faa75e397c667b6d5b8d98b3b.1474177609.git.baolin.wang@linaro.org> <0d5cedb2f4ad46aa7fb07b990072bacb33517102.1474177609.git.baolin.wang@linaro.org> <alpine.DEB.2.20.1609202340560.5476@nanos> <CAMz4kuLYkyZzs33VKmo9B3JxTFFDYun7AHBYUUmHz=424yiq8g@mail.gmail.com>
 <alpine.DEB.2.20.1609210919390.5573@nanos> <20160921083305.24524304@gandalf.local.home>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 21 Sep 2016, Steven Rostedt wrote:
> On Wed, 21 Sep 2016 09:26:20 +0200 (CEST)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> > A single u64 does not take more storage space than this and it's a single
> > store.
> 
> So to use rtc_tm_to_time64()? Is the work to do the calculations of the
> conversion faster than a bunch of stores that are going to be in hot
> cache?

Look at the call site. It has already the scalar nsec value and it does a
conversion to rtc time in order to trace it.

Ditto for the other tracepoints where the conversion from scalar nsec is
done in the tracepoint itself.

Thanks,

	tglx