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[89.186.78.87]) by smtp.gmail.com with ESMTPSA id h20sm3377489wmb.1.2021.03.05.01.18.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Mar 2021 01:18:09 -0800 (PST) Message-ID: <014e41015f59d4be9a816398302e892897efb244.camel@gmail.com> Subject: Re: [RFC] Open multiple trace files and, if possible, pair them From: raistlin.df@gmail.com To: Stefano De Venuto , rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Date: Fri, 05 Mar 2021 10:18:07 +0100 In-Reply-To: <20210305062807.2734-1-stefano.devenuto99@gmail.com> References: <20210305062807.2734-1-stefano.devenuto99@gmail.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.4 (by Flathub.org) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Hi Stefano! Great to see your patch here on the list! :-) On Fri, 2021-03-05 at 07:28 +0100, Stefano De Venuto wrote: > The goal of this patch is to teach to trace-cmd how to open multiple > files and, if they are generated by an host and some guests, pair and > synchronize them. > > We do that by checking, for every input file, whether or not > it has a corresponding peer, and if that's the case pairs them. > Exactly. So, for the trace-devel community: our (Stefano's and mine :-D) end goal is to do some analysis & manipulation on a combined host+guest(s) trace file. Of course, in order to do that, we need a nice and easy way to get such a trace file! Implementing the support for that in trace-cmd seemed the most reasonable first step, so we reached out and decided to work on https://bugzilla.kernel.org/show_bug.cgi?id=211657 , which is what this patch does. Now ... > We know that the code must be changed following the new API, but we > would like to have an opinion on the work done so far. > ... the API is changing, so we'll have to adapt it. Still, the patch includes, e.g., the logic for opening multiple trace files and figuring out whether they are guest or host, etc. And maybe these bits are still valid and you're able/willing to give us some feedback on whether they make sense? :-) > Signed-off-by: Stefano De Venuto > --- >  tracecmd/trace-read.c | 35 +++++++++++++++++++++++++++++++++++ >  1 file changed, 35 insertions(+) > For Stefano: about the patch itself, I think the only thing I'm going to say is that some of the lines look a bit long. I do not see a CODING_STYLE file in the repo, but just looking around, I got the impression that we should stay within 76-80 characters all the times that it is possible. And that's it, and I'm happy to let the experts speak, as I'm only trying to learn trace-cmd internals myself. ;-D Thanks and Regards -- Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <> (Raistlin Majere)