Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759158Ab2EPRY2 (ORCPT ); Wed, 16 May 2012 13:24:28 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:9722 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753870Ab2EPRY1 (ORCPT ); Wed, 16 May 2012 13:24:27 -0400 X-Authority-Analysis: v=2.0 cv=ae7jbGUt c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=IXDOenSsrcIA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=wYfDrUjZNtrk5NmWzDoA:9 a=cdZg3o63KdCmHFXO4dcA:7 a=PUjeQqilurYA:10 a=jeBq3FmKZ4MA:10 a=0Wy_TWe8l2NOzAJH:21 a=P5LyYogyyaPfNIJS:21 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1337189065.6724.55.camel@gandalf.stny.rr.com> Subject: [RFC][PATCH v2] tracing: Remove useless 4 bytes of padding from every event From: Steven Rostedt To: LKML Cc: Arjan van de Ven , Linus Torvalds , Ingo Molnar , Frederic Weisbecker , David Sharp , Vaibhav Nagarnaik , Peter Zijlstra , Andrew Morton Date: Wed, 16 May 2012 13:24:25 -0400 In-Reply-To: <1337175871.6724.46.camel@gandalf.stny.rr.com> References: <1337175871.6724.46.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2072 Lines: 60 On Wed, 2012-05-16 at 09:44 -0400, Steven Rostedt wrote: > Now that PowerTop v2 is out, which uses the parse-event library, it no > longer is broken by the removal of the lock-depth field from every > event. Currently we add 4 bytes of empty space to every event. If we > have 1 million events, 4 million bytes are wasted in the ring buffers > (for both ftrace and perf). > > But this change will break PowerTop v1. Thus my question is, how long do > we need to keep this wasted space in the ring buffers to satisfy an out > of date tool? > Would help if I compiled it :-) Signed-off-by: Steven Rostedt diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 5f3f3be..f96dfef 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -49,7 +49,6 @@ struct trace_entry { unsigned char flags; unsigned char preempt_count; int pid; - int padding; }; #define FTRACE_MAX_EVENT \ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 08a08ba..0960aa7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1145,7 +1145,6 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, entry->preempt_count = pc & 0xff; entry->pid = (tsk) ? tsk->pid : 0; - entry->padding = 0; entry->flags = #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) | diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 079a93a..5845731 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -116,7 +116,6 @@ static int trace_define_common_fields(void) __common_field(unsigned char, flags); __common_field(unsigned char, preempt_count); __common_field(int, pid); - __common_field(int, padding); return ret; } -- 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/