[lttng-dev] Best way to analyze CTF files

[Eugene Ivanov]

Hi Sebastian,

In our company one of the main lttng applications is to measure latency
between two probes which get same ID as argument. For this purpose we've
implemented in C a special utility which is based on libraries to read CTF
(IIRC). Also some developers often use own simple perl scripts to analyze
babeltrace output.
I wish there is a better way to implement custom CTF analyzers, probably
some basic DSL.


On Sat, Oct 18, 2014 at 2:23 AM, Boisvert, Sebastien <boisvert at anl.gov>
wrote:

> Bonjour,
>
> First, thank you for LTTng-UST. This is very useful and convenient.
>
> I just got started today using LTTng (LTTng-UST) for tracing a HPC
> application
> that I am working on (I am a postdoc). I am impressed by how easy LTTng is
> to use it.
>
> In my system, an actor message is represented by a pair
> <message_actor_source, message_number>.
>
> I want to list all messages that have a high delivery time
> (message:actor_receive - message:actor_send).
>
> I am doing this to get the messages of one actor (actor 1000019):
>
> [boisvert at bigmem biosal]$ babeltrace
> ~/lttng-traces/auto-20141017-181240|grep "message_source_actor = 1000019"
> > actor_1000019
>
> Then, I can look at one message with (message <1000019, 14>):
>
> [boisvert at bigmem biosal]$ grep "message_number = 14," actor_1000019
> [18:12:43.647017211] (+0.000005110) bigmem.knoxville.kbase.us
> message:actor_send: { cpu_id = 30 }, { message_number = 14, message_action
> = 31592, message_count = 8, message_source_actor = 1000019,
> message_destination_actor = 1000059, message_source_node = -1,
> message_destination_node = -1 }
> [18:12:43.647025249] (+0.000002860) bigmem.knoxville.kbase.us
> message:actor_receive: { cpu_id = 49 }, { message_number = 14,
> message_action = 31592, message_count = 8, message_source_actor = 1000019,
> message_destination_actor = 1000059, message_source_node = 3,
> message_destination_node = 3 }
>
> If I substract the times:
>
> irb(main):003:0> (43.647025249-43.647017211)*10**9
> => 8038.00000426236
>
> This message (<1000019, 14>) required 8038 ns for the delivery. This one
> is fine.
>
>
> So basically my question is:
>
> Is there an easy way to analyze these tracepoint files ?
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>



-- 
Eugene
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