From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753948AbdKFPwh (ORCPT ); Mon, 6 Nov 2017 10:52:37 -0500 Received: from mga06.intel.com ([134.134.136.31]:6638 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753177AbdKFPwf (ORCPT ); Mon, 6 Nov 2017 10:52:35 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,353,1505804400"; d="scan'208";a="146518016" Message-ID: <1509983553.27629.2.camel@tzanussi-mobl.amr.corp.intel.com> Subject: Re: [PATCH v4 06/37] ring-buffer: Redefine the unimplemented RINGBUF_TYPE_TIME_STAMP From: Tom Zanussi To: Namhyung Kim Cc: rostedt@goodmis.org, tglx@linutronix.de, mhiramat@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel.opensrc@gmail.com, joelaf@google.com, mathieu.desnoyers@efficios.com, baohong.liu@intel.com, rajvi.jingar@intel.com, julia@ni.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, kernel-team@lge.com Date: Mon, 06 Nov 2017 09:52:33 -0600 In-Reply-To: <20171106050953.GA7557@sejong> References: <8927a4736dc6f602079d0797b60d3bf7a5d2d9d7.1509395595.git.tom.zanussi@linux.intel.com> <20171106050953.GA7557@sejong> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Namhyung, On Mon, 2017-11-06 at 14:09 +0900, Namhyung Kim wrote: > Hi Tom, > > On Mon, Oct 30, 2017 at 03:51:48PM -0500, Tom Zanussi wrote: > > RINGBUF_TYPE_TIME_STAMP is defined but not used, and from what I can > > gather was reserved for something like an absolute timestamp feature > > for the ring buffer, if not a complete replacement of the current > > time_delta scheme. > > > > This code redefines RINGBUF_TYPE_TIME_STAMP to implement absolute time > > stamps. Another way to look at it is that it essentially forces > > extended time_deltas for all events. > > > > The motivation for doing this is to enable time_deltas that aren't > > dependent on previous events in the ring buffer, making it feasible to > > use the ring_buffer_event timetamps in a more random-access way, for > > purposes other than serial event printing. > > > > To set/reset this mode, use tracing_set_timestamp_abs() from the > > previous interface patch. > > > > Signed-off-by: Tom Zanussi > > --- > > [SNIP] > > @@ -2220,13 +2246,16 @@ static void rb_inc_iter(struct ring_buffer_iter *iter) > > } > > > > /* Slow path, do not inline */ > > -static noinline struct ring_buffer_event * > > +static struct noinline ring_buffer_event * > > struct noinline? Looks like a mistake.. > Yeah, it is, not sure how that could have even happened, sheesh. Thanks for pointing it out, Tom