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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12098C7618E for ; Mon, 24 Apr 2023 22:26:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231364AbjDXW02 (ORCPT ); Mon, 24 Apr 2023 18:26:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45018 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232588AbjDXW00 (ORCPT ); Mon, 24 Apr 2023 18:26:26 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01B47A5F7 for ; Mon, 24 Apr 2023 15:25:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4CABB6267C for ; Mon, 24 Apr 2023 22:25:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5077C433EF; Mon, 24 Apr 2023 22:25:55 +0000 (UTC) Date: Mon, 24 Apr 2023 18:25:54 -0400 From: Steven Rostedt To: Vladimir Oltean Cc: Masami Hiramatsu , Andrew Lunn , netdev@vger.kernel.org, Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Florian Fainelli Subject: Re: [PATCH net-next 0/2] DSA trace events Message-ID: <20230424182554.642bc0fc@rorschach.local.home> In-Reply-To: <20230421124708.tznoutsymiirqja2@skbuf> References: <20230407141451.133048-1-vladimir.oltean@nxp.com> <20230412095534.dh2iitmi3j5i74sv@skbuf> <20230421213850.5ca0b347e99831e534b79fe7@kernel.org> <20230421124708.tznoutsymiirqja2@skbuf> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 21 Apr 2023 15:47:08 +0300 Vladimir Oltean wrote: > On Fri, Apr 21, 2023 at 09:38:50PM +0900, Masami Hiramatsu wrote: > > If the subsystem maintainers are OK for including this, it is OK. > > But basically, since the event is exposed to userland and you may keep > > these events maintained, you should carefully add the events. > > If those are only for debugging (after debug, it will not be used > > frequently), can you consider to use kprobe events? > > 'perf probe' command will also help you to trace local variables and > > structure members as like gdb does. > > Thanks for taking a look. I haven't looked at kprobe events. I also > wasn't planning on maintaining these assuming stable UABI terms, just > for debugging. What are some user space consumers that expect the UABI > to be stable, and what is it about the trace events that can/can't change? Ideally, tooling will use the libtraceevent library[1] to parse the events. In that case, if an event is used by tooling, you'll need to keep around the fields that are used by the tooling. -- Steve [1] https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/