Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753678AbdLMQqe (ORCPT ); Wed, 13 Dec 2017 11:46:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:55838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753356AbdLMQqc (ORCPT ); Wed, 13 Dec 2017 11:46:32 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D7261218BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Wed, 13 Dec 2017 11:46:29 -0500 From: Steven Rostedt To: Mark Brown Cc: Alexandre Belloni , Arnd Bergmann , Baolin Wang , Alessandro Zummo , Ingo Molnar , linux-rtc@vger.kernel.org, LKML Subject: Re: [PATCH v2] rtc: Add tracepoints for RTC system Message-ID: <20171213114629.1beaa9c8@gandalf.local.home> In-Reply-To: <20171213121603.GF6416@sirena.org.uk> References: <64a38f4a15a2f8dae4a9fd0a3fc2a312e86c733d.1510749847.git.baolin.wang@linaro.org> <20171212221643.GL8318@piout.net> <20171213110426.GQ8318@piout.net> <20171213121603.GF6416@sirena.org.uk> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 842 Lines: 19 On Wed, 13 Dec 2017 12:16:03 +0000 Mark Brown wrote: > On Wed, Dec 13, 2017 at 12:04:26PM +0100, Alexandre Belloni wrote: > > > Also, I think we could try having only the time64_t in the ring buffer. > > Maybe I'm wrong but I think tools reading that buffer can do the > > conversion themselves. Maybe I don't understand correctly how > > tracepoints work and this doesn't make sense, tell me. > > Tools reading the buffer can do the conversion themselves but it's also > useful for users to just view the log directly via tracing/trace > sometimes. OTOH the whole point is to be low overhead so... Ideally, we want TP_fast_assign() do as little as possible, and put all the work in TP_printk() as the printk happens on read of the trace buffer and TP_fast_assign() happens at the tracepoint invocation. -- Steve