From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rocky Dunlap via lttng-dev Subject: bt2 Python quick start/examples? Date: Wed, 11 Mar 2020 22:56:24 -0400 Message-ID: Reply-To: Rocky Dunlap Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============6214665854443151921==" Return-path: Received: from mail-oi1-x22c.google.com (mail-oi1-x22c.google.com [IPv6:2607:f8b0:4864:20::22c]) by lists.lttng.org (Postfix) with ESMTPS id 48dD4V1D1Rz1GVl for ; Wed, 11 Mar 2020 22:56:41 -0400 (EDT) Received: by mail-oi1-x22c.google.com with SMTP id p125so4036545oif.10 for ; Wed, 11 Mar 2020 19:56:41 -0700 (PDT) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" To: lttng-dev@lists.lttng.org List-Id: lttng-dev@lists.lttng.org --===============6214665854443151921== Content-Type: multipart/alternative; boundary="000000000000900fac05a09f80e0" --000000000000900fac05a09f80e0 Content-Type: text/plain; charset="UTF-8" I see that the bt2 Python documentation is not yet ready: https://babeltrace.org/docs/v2.0/python/bt2/ In lieu of that, where is the best place to find at least a few examples of using the bt2 Python API for basic trace processing tasks? Thanks, Rocky --000000000000900fac05a09f80e0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

I see that the bt2 Python documentation is not yet ready:<= div>https://babelt= race.org/docs/v2.0/python/bt2/

In lieu of = that, where is the best place to find at least a few examples of using the = bt2 Python API for basic trace processing tasks?

T= hanks,

Rocky

--000000000000900fac05a09f80e0-- --===============6214665854443151921== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev --===============6214665854443151921==-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Rajotte-Julien via lttng-dev Subject: Re: bt2 Python quick start/examples? Date: Thu, 12 Mar 2020 10:18:41 -0400 Message-ID: <20200312141841.GB16241@joraj-alpa> References: Reply-To: Jonathan Rajotte-Julien Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lists.lttng.org (Postfix) with ESMTPS id 48dWCX6FCZz1H80 for ; Thu, 12 Mar 2020 10:18:48 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id CCFBA28130A for ; Thu, 12 Mar 2020 10:18:42 -0400 (EDT) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" To: Rocky Dunlap Cc: lttng-dev@lists.lttng.org List-Id: lttng-dev@lists.lttng.org Hi, On Wed, Mar 11, 2020 at 10:56:24PM -0400, Rocky Dunlap via lttng-dev wrote: > I see that the bt2 Python documentation is not yet ready: > https://babeltrace.org/docs/v2.0/python/bt2/ Slowly getting there. > > In lieu of that, where is the best place to find at least a few examples of > using the bt2 Python API for basic trace processing tasks? Simon Marchi have some examples [1] that have been used in his talk [2][3]. Hope this helps a bit. [1] https://github.com/simark/babeltrace-fun-plugins [2] https://www.youtube.com/watch?v=P3cPISvW444&feature=youtu.be [3] https://tracingsummit.org/ts/2019/files/Tracingsummit2019-babeltrace2-marchi.pdf -- Jonathan Rajotte-Julien EfficiOS From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Marchi via lttng-dev Subject: Re: bt2 Python quick start/examples? Date: Thu, 12 Mar 2020 11:58:02 -0400 Message-ID: References: <20200312141841.GB16241@joraj-alpa> Reply-To: Simon Marchi Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from simark.ca (simark.ca [158.69.221.121]) by lists.lttng.org (Postfix) with ESMTPS id 48dYQ942Ppz1HHY for ; Thu, 12 Mar 2020 11:58:09 -0400 (EDT) In-Reply-To: <20200312141841.GB16241@joraj-alpa> Content-Language: tl List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" To: Jonathan Rajotte-Julien , Rocky Dunlap Cc: lttng-dev@lists.lttng.org List-Id: lttng-dev@lists.lttng.org On 2020-03-12 10:18 a.m., Jonathan Rajotte-Julien via lttng-dev wrote: > Hi, > > On Wed, Mar 11, 2020 at 10:56:24PM -0400, Rocky Dunlap via lttng-dev wrote: >> I see that the bt2 Python documentation is not yet ready: >> https://babeltrace.org/docs/v2.0/python/bt2/ > > Slowly getting there. > >> >> In lieu of that, where is the best place to find at least a few examples of >> using the bt2 Python API for basic trace processing tasks? > > Simon Marchi have some examples [1] that have been used in his talk [2][3]. > > Hope this helps a bit. > > > [1] https://github.com/simark/babeltrace-fun-plugins > [2] https://www.youtube.com/watch?v=P3cPISvW444&feature=youtu.be > [3] https://tracingsummit.org/ts/2019/files/Tracingsummit2019-babeltrace2-marchi.pdf In my presentation, I only touched the subject of writing component classes in Python. I think that what many people are looking for is how to read a trace from Python, perhaps using existing component classes, to quickly prototype/implement some analysis. So let me provide some small examples here to get people started, until the formal documentation is completed. If all you want to do is iterate on all the events of a trace or trace collection, then the most convenient/high-level entry point is the bt2.TraceCollectionMessageIterator class. It works similarly to the Babeltrace 2 CLI's convert command, in that you can just pass it an input string (a file path, a directory path or an arbitrary string recognized by some source component class) and it will use the auto-discovery mechanism to figure out which source components to instantiate. You can also pass it more precise configurations of components to instantiate if needed, as well as various flags similar to what the CLI's convert command accepts (begin, end, stream-intersection). Here's a simple example that iterates on an LTTng kernel trace: import bt2 it = bt2.TraceCollectionMessageIterator( "/home/smarchi/lttng-traces/auto-20191016-165642" ) for msg in it: if type(msg) == bt2._EventMessageConst: ev = msg.event if ev.cls.name == "sched_switch": cpu = ev.packet.context_field["cpu_id"] prev_tid = ev.payload_field["prev_tid"] next_tid = ev.payload_field["next_tid"] print( "cpu {}: switching from tid {} to tid {}".format( cpu, prev_tid, next_tid ) ) Here's another example that shows how to instantiate a graph manually, add and connects ports to it and run it. It connects a "source.text.dmesg" source with a "sink.text.details" sink and runs the graph until completion. import bt2 g = bt2.Graph() source = g.add_component( bt2.find_plugin("text").source_component_classes["dmesg"], "source" ) sink = g.add_component( bt2.find_plugin("text").sink_component_classes["details"], "sink" ) g.connect_ports(source.output_ports["out"], sink.input_ports["in"]) g.run() Without any parameters, the source.text.dmesg component reads on standard input, so you can execute this example with: $ dmesg | python3 example.py For more examples of what these types can do, you can always look at the test cases: https://github.com/efficios/babeltrace/tree/master/tests/bindings/python/bt2 Hope this helps for the moment, Simon