Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753367AbZDMViU (ORCPT ); Mon, 13 Apr 2009 17:38:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752274AbZDMViG (ORCPT ); Mon, 13 Apr 2009 17:38:06 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:55892 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751122AbZDMViD (ORCPT ); Mon, 13 Apr 2009 17:38:03 -0400 Date: Mon, 13 Apr 2009 23:37:45 +0200 From: Ingo Molnar To: "Theodore Ts'o" , Steven Rostedt , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker Cc: Linux Kernel Developers List Subject: Re: [PATCH 2/2] ext4: Convert instrumentation from markers to tracepoints Message-ID: <20090413213745.GC8514@elte.hu> References: <20090412172344.GC10547@mit.edu> <1239557566-3411-1-git-send-email-tytso@mit.edu> <1239557566-3411-2-git-send-email-tytso@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1239557566-3411-2-git-send-email-tytso@mit.edu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2341 Lines: 57 * Theodore Ts'o wrote: > Signed-off-by: "Theodore Ts'o" > --- > fs/ext4/ext4.h | 22 +-- > fs/ext4/ext4_i.h | 12 - > fs/ext4/fsync.c | 8 +- > fs/ext4/ialloc.c | 17 +- > fs/ext4/inode.c | 79 ++--- > fs/ext4/mballoc.c | 84 ++--- > fs/ext4/mballoc.h | 68 +---- > fs/ext4/super.c | 6 +- > include/linux/ext4_trace_types.h | 108 ++++++ > include/trace/ext4.h | 8 + > include/trace/ext4_event_types.h | 690 +++++++++++++++++++++++++++++++++++++ > include/trace/trace_event_types.h | 1 + > include/trace/trace_events.h | 1 + > 13 files changed, 886 insertions(+), 218 deletions(-) > create mode 100644 include/linux/ext4_trace_types.h > create mode 100644 include/trace/ext4.h > create mode 100644 include/trace/ext4_event_types.h Really nice stuff! A general, high-level observation: it is visible that the conversion to TRACE_EVENTS() does increase the total linecount, but it also removes code from the most often used source code areas (fs/ext4/*.c) - and using an intuitive function-call-alike single-line tracepoint there. I'd call that a positive effect. It would still be nice to compact the 690 lines of (out of line) ext4_event_types.h definitions some more - and i think we'll be able to do it without affecting the usage sites. OTOH, even those bits look fairly readable, and there's a fair amount of bang-for-bucks ratio - these tracepoints give us: - integrated tracepoints - zero-copy and per-cpu splice() based tracing - binary tracing without printf overhead - structured logging records exposed under /debug/tracing/events - trace events embedded in function tracer output and other plugins - user-defined, per tracepoint filter expressions ... so even if we were to keep the 690 lines of overhead with no further compacting, it still looks like a good deal to me, all things considered. Ingo -- 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/