From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE9FE25DAF0; Tue, 9 Sep 2025 18:39:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757443148; cv=none; b=egbE/n/oqKsyHBaQMp7kUlA1+IAz+x0kXRypFlBL+TM6dM/gMaVVeyq1jkvxDYf0Dn2pCXJVBSL+V5+QUSnzkWscDwmT5UidQtpW93V7JvtQa2Kez2+mBe13KR3dpfe/g0H1LsI7wsAUxyFRtzZBSev6jCTRG467PCs3U+zHypA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757443148; c=relaxed/simple; bh=eqcE62nxhCYT/g1eduv2zGQJ99h5K0JxSzmZu9RmBP4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=b4nsspJv1rAJPBxz1L+eKyloJ130+ZRAZcNCfEkXt1agNHw5G77EAmiPtXtx+NDbxo6sBDmMi7dYLtCl5cHX4qm5d4n47UiOa0Jfuuj+rSU3KUriXP29izaUUxt6R+v64uqIUA1cU7K+Fd723r7ysIbNpNU42jnKtXmhCwDgoAw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 69E5A14069C; Tue, 9 Sep 2025 18:39:04 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf20.hostedemail.com (Postfix) with ESMTPA id B2FDE20025; Tue, 9 Sep 2025 18:39:00 +0000 (UTC) Date: Tue, 9 Sep 2025 14:39:48 -0400 From: Steven Rostedt To: Vincent Donnefort Cc: mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 04/24] tracing: Add reset to trace remotes Message-ID: <20250909143948.420bfb1c@gandalf.local.home> In-Reply-To: References: <20250821081412.1008261-1-vdonnefort@google.com> <20250821081412.1008261-5-vdonnefort@google.com> <20250908193757.079aae76@gandalf.local.home> <20250909094028.3265b751@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: B2FDE20025 X-Stat-Signature: 88rpahm4umjmmcjmrz9w7j3z6z8cjawb X-Rspamd-Server: rspamout02 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1/Dfb0F/ok0yMi6rVU9qwiXjkJqxDcdMLk= X-HE-Tag: 1757443140-354827 X-HE-Meta: U2FsdGVkX1/dFMJGRD+C6O+Za+iRGR7QlQeUizfNtukq1m6fiS7yJXJxYQxG9yxfVWgqP1DYfzB0aOk3vcc97HywbUnaMvNe17yZQK7V0szWK1Xn6Fl1E/CQyXQAKRnkuCgAc7SuJp0V/GjwyvI52PlbVs4xIb6J5bfiz08Jgs1BYuK2BxX9Q4cDppfKLQ5O3V9K0Fdd3muKjQcb4613ryQc1TiRocoDXYvOIhxEJ3hsZTAKZllg5vzY8IgoDRAIEVes+/4idN+hXi8UaE6BF780N6C1bIYBKIOoWDOENiR/Vg6w8f57zdLTvf6x0jOhYSOnHsTZAQiFGZjiGXvDuz1xkAnD1qwI On Tue, 9 Sep 2025 17:14:35 +0100 Vincent Donnefort wrote: > On Tue, Sep 09, 2025 at 09:40:28AM -0400, Steven Rostedt wrote: > > On Tue, 9 Sep 2025 13:10:25 +0100 > > Vincent Donnefort wrote: > > > > > > I wonder if we should name the file "reset" to not be confusing to users > > > > when they cat the file and it doesn't produce any output. > > > > > > My idea was to keep the exact same interface as the rest of the tracing. I could > > > keep that /trace file for compatibility and add /reset? > > > > > > "cat trace" could also just returns a text like *** not supported *** ? > > > > If it's never going to be supported, I rather not add it. It not being > > there is a sure way of knowing it's not supported. Just adding it because > > the normal system has it is actually worse if it doesn't behave the same. > > If later we extend the meta-page to support non-consuming read, /trace would > then become useful. > > Another argument for non-consuming read would be to enable dump on panic. > > But I understand your point, it might be wishful thinking at this point. > It may be possible to still do a trace file. Basically, it would work the same way the normal iterator works. Today it reads the trace while the writer could be modifying it. Actually, I think there's a bug in the iterator code today :-p It needs to be modified to copy the event, as it currently passes the event as is and that event could be written over by the writer. But anyway, I think it should work for the remote buffers too. Let me go and fix the current iterator. -- Steve