From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 6E66249B for ; Sat, 24 Jun 2017 11:14:19 +0000 (UTC) Received: from osg.samsung.com (ec2-52-27-115-49.us-west-2.compute.amazonaws.com [52.27.115.49]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id C02A4AB for ; Sat, 24 Jun 2017 11:14:18 +0000 (UTC) Date: Sat, 24 Jun 2017 08:14:11 -0300 From: Mauro Carvalho Chehab To: Steven Rostedt Message-ID: <20170624081411.58b4fb6a@vento.lan> In-Reply-To: <20170619122651.57ba27c4@gandalf.local.home> References: <20170619052146.GA2889@jagdpanzerIV.localdomain> <20170619103912.2edbf88a@gandalf.local.home> <20170619152055.GM3786@lunn.ch> <20170619122651.57ba27c4@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: ksummit-discuss@lists.linuxfoundation.org Subject: Re: [Ksummit-discuss] [TECH TOPIC] printk redesign List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Em Mon, 19 Jun 2017 12:26:51 -0400 Steven Rostedt escreveu: > On Mon, 19 Jun 2017 17:20:55 +0200 > Andrew Lunn wrote: > > > > > 4) All other kernel information that's not critical at all, and perhaps > > > doesn't even need to be serialized. At least, not against the above. > > > This could be cached, and outputted at a later time than when the > > > printk() was called. > > > > Developers machine probably have different requirements to production > > machines. When debugging during code development, i want the debug > > output to be in the correct order, independent of the level. If you > > are going to cause reordering, you might want to add a sequence number > > to each output, so it is possible to put it back into the correct > > order. And it needs to be clear when output is out of order. Even for developers, ensuring the correct order is a must. If someone reports me a bug that the Kernel crashed because of some driver, I would ask him to enable debug messages and send the crash logs with it enabled. > Perhaps a kernel command line option could force this. I'd say that a Kconfig option can also be used for that. In the case of media, we have a config option that enables extra debugging features (CONFIG_VIDEO_ADV_DEBUG). It seems that other subsystems have similar things: $ grep ADV .config|grep DEB CONFIG_PM_ADVANCED_DEBUG=y CONFIG_BATMAN_ADV_DEBUGFS=y CONFIG_BATMAN_ADV_DEBUG=y CONFIG_VIDEO_ADV_DEBUG=y Well, if any of such options are selected, I'd say that ordering the logs should be the default. Thanks, Mauro