From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 518CDC433DF for ; Sat, 27 Jun 2020 01:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FDAF208B6 for ; Sat, 27 Jun 2020 01:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726522AbgF0BNx (ORCPT ); Fri, 26 Jun 2020 21:13:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726315AbgF0BNw (ORCPT ); Fri, 26 Jun 2020 21:13:52 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1CEFB2145D; Sat, 27 Jun 2020 01:13:51 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.93) (envelope-from ) id 1jozPh-003zXZ-UE; Fri, 26 Jun 2020 21:13:49 -0400 Message-ID: <20200627011349.816080573@goodmis.org> User-Agent: quilt/0.66 Date: Fri, 26 Jun 2020 21:00:43 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Mathieu Desnoyers , Peter Zijlstra , Thomas Gleixner , Masami Hiramatsu , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Yordan Karadzhov , Tzvetomir Stoyanov , Tom Zanussi , Jason Behmer , Julia Lawall , Clark Williams , bristot , Daniel Wagner , Darren Hart , Jonathan Corbet , "Suresh E. Warrier" Subject: [PATCH 2/3] ring-buffer: Incorporate absolute timestamp into add_timestamp logic References: <20200627010041.517736087@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" Instead of calling out the absolute test for each time to check if the ring buffer wants absolute time stamps for all its recording, incorporate it with the add_timestamp field and turn it into flags for faster processing between wanting a absolute tag and needing to force one. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 42 +++++++++++++++++++++----------------- 1 file changed, 23 insertions(+), 19 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 4f13ae38b8f8..986ddc8eba93 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -422,13 +422,15 @@ struct rb_event_info { /* * Used for the add_timestamp * NONE - * NORMAL - may be for either time extend or absolute + * EXTEND - wants a time extend + * ABSOLUTE - the buffer requests all events to have absolute time stamps * FORCE - force a full time stamp. */ enum { - RB_ADD_STAMP_NONE, - RB_ADD_STAMP_NORMAL, - RB_ADD_STAMP_FORCE + RB_ADD_STAMP_NONE = 0, + RB_ADD_STAMP_EXTEND = BIT(1), + RB_ADD_STAMP_ABSOLUTE = BIT(2), + RB_ADD_STAMP_FORCE = BIT(3) }; /* * Used for which event context the event is in. @@ -2435,8 +2437,8 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer, * add it to the start of the reserved space. */ if (unlikely(info->add_timestamp)) { - bool abs = info->add_timestamp == RB_ADD_STAMP_FORCE || - ring_buffer_time_stamp_abs(cpu_buffer->buffer); + bool abs = info->add_timestamp & + (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE); event = rb_add_time_stamp(event, abs ? info->delta : delta, abs); length -= RB_LEN_TIME_EXTEND; @@ -2885,8 +2887,8 @@ int ring_buffer_unlock_commit(struct trace_buffer *buffer, EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit); static noinline void -rb_handle_timestamp(struct ring_buffer_per_cpu *cpu_buffer, - struct rb_event_info *info) +rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer, + struct rb_event_info *info) { WARN_ONCE(info->delta > (1ULL << 59), KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s", @@ -2898,7 +2900,6 @@ rb_handle_timestamp(struct ring_buffer_per_cpu *cpu_buffer, "please switch to the trace global clock:\n" " echo global > /sys/kernel/debug/tracing/trace_clock\n" "or add trace_clock=global to the kernel command line\n"); - info->add_timestamp = RB_ADD_STAMP_NORMAL; } static struct ring_buffer_event * @@ -2908,8 +2909,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, struct ring_buffer_event *event; struct buffer_page *tail_page; unsigned long tail, write, w, next; - u64 delta, before, after; - bool abs = false; + u64 before, after; /* Don't let the compiler play games with cpu_buffer->tail_page */ tail_page = info->tail_page = READ_ONCE(cpu_buffer->tail_page); @@ -2923,20 +2923,23 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, if (ring_buffer_time_stamp_abs(cpu_buffer->buffer)) { info->delta = info->ts; - abs = true; + info->add_timestamp = RB_ADD_STAMP_ABSOLUTE; } else { info->delta = info->ts - after; } - if (unlikely(test_time_stamp(info->delta))) - rb_handle_timestamp(cpu_buffer, info); + if (unlikely(test_time_stamp(info->delta))) { + rb_check_timestamp(cpu_buffer, info); + info->add_timestamp |= RB_ADD_STAMP_EXTEND; + } /* * If interrupting an event time update, we may need an absolute timestamp. * Don't bother if this is the start of a new page (w == 0). */ if (unlikely(before != after && w)) - info->add_timestamp = RB_ADD_STAMP_FORCE; + info->add_timestamp |= RB_ADD_STAMP_FORCE | RB_ADD_STAMP_EXTEND; + /* * If the time delta since the last event is too big to * hold in the time field of the event, then we append a @@ -2976,7 +2979,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /*D*/ local64_set(&cpu_buffer->write_stamp, info->ts); barrier(); /*E*/ save_before = local64_read(&cpu_buffer->before_stamp); - if (likely(info->add_timestamp != RB_ADD_STAMP_FORCE)) + if (likely(!(info->add_timestamp & + (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE)))) /* This did not interrupt any time update */ info->delta = info->ts - after; else @@ -3019,15 +3023,15 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, */ info->delta = 0; } - if (info->add_timestamp == RB_ADD_STAMP_FORCE) - info->add_timestamp = RB_ADD_STAMP_NORMAL; + info->add_timestamp &= ~RB_ADD_STAMP_FORCE; } /* * If this is the first commit on the page, then it has the same * timestamp as the page itself. */ - if (unlikely(!tail && info->add_timestamp != RB_ADD_STAMP_FORCE && !abs)) + if (unlikely(!tail && !(info->add_timestamp & + (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE)))) info->delta = 0; /* We reserved something on the buffer */ -- 2.26.2