[lttng-dev] Problem with perf:thread in 2.5.0
Evgeniy Ivanov
i at eivanov.com
Fri Jul 25 15:33:56 EDT 2014
Hey Jonathan,
Thanks a lot for help! I think I've found the reason of invalid context
messages: I reran root's lttng-sessiond, but didn't check sessions for my
user (since I've done 'destroy -a'). Today again I got issue with invalid
context and noticed, that there are two pairs of lttng-sessiond
and lttng-consumerd: from old version and from new version according dates.
Old one is from July 7, which is surprising, since I often do "destroy -a".
After killing everything seems to work. Btw, it's Oracle linux 6.5 with
linux 3.8.
I'll check that zeros after weekend: I don't have own access to that
machine.
On Fri, Jul 25, 2014 at 1:07 AM, Jonathan Rajotte-Julien <
jonathan.rajotte-julien at ericsson.com> wrote:
>
>
> On 07/24/2014 04:46 PM, Jonathan Rajotte-Julien wrote:
> >
> > Hey Evgeniy,
> >
> >
> >> Jonathan, sorry, I've copied wrong output, original command was with
> perf:thread:cpu-cycles:
> >>
> >>> lttng add-context -u -t vpid -t perf:thread:cpu-cycles -t
> perf:thread:instructions -t perf:thread:cache-misses
> >> Session auto-20140724-091524 created.
> >> Traces will be written in
> /export/home/eiva/lttng-traces/auto-20140724-091524
> >> UST context vpid added to all channels
> >> Error: perf:thread:cpu-cycles: UST invalid context
> >> Error: perf:thread:instructions: UST invalid context
> >> Error: perf:thread:cache-misses: UST invalid context
> >> Warning: Some command(s) went wrong
> >> UST event eiva_test:* created in channel channel0
> >
> > Weird, it works on my side (c&p) with latest version witch is 2.5 stable
> :P.
>
> I just tested a fresh install from stable ppa (
> https://launchpad.net/~lttng/+archive/ubuntu/ppa).
>
> and everything seems to work fine. Cycle,cache etc.
>
> Well, keep us up to date.
>
> Cheers
> Jonathan
>
> >
> >>
> >>> lttng --version
> >> lttng (LTTng Trace Control) 2.5.0 - Fumisterie
> >
> > From this output I guess you are working with the lttng package and not
> the source from git. I don't think packaging is the problem here but let
> just keep that in mind.
> > What dist are you on ?
> >
> > I'm sure you already done it a thousand time but could you just run
> these and send the output ?
> >
> > First make sure no lttng-sessiond is running then launch:
> >
> > lttng-sessiond -vvv
> >
> > In a separate terminal:
> >
> > lttng destroy -a // Just in case
> > lttng -vvv create test
> >
> > lttng -vvv add-context -u -t vpid -t perf:thread:cpu-cycles -t
> perf:thread:instructions -t perf:thread:cache-misses
> >
> > If this work, you could test if you get the data or zero.
> >
> > lttng enable-event -u -a -s test
> >
> > lttng start
> > // Run the program
> >
> > lttng stop
> >
> > Make sure to send the output from lttng-sessiond -vvv.
> >
> >
> > Cheers,
> > Jonathan
> >
> >>
> >> Later I've tried cpu-cycles separately and then accidentally switched
> to perf:cpu. Now everything started to work, but nothing changed since
> then. Though didn't check if we still get zeroes on another machine.
> >>
> >>
> >> On Thu, Jul 24, 2014 at 7:01 PM, Jonathan Rajotte-Julien <
> jonathan.rajotte-julien at ericsson.com <mailto:
> jonathan.rajotte-julien at ericsson.com>> wrote:
> >>
> >> Hi!
> >>
> >> > Hi!
> >> >
> >> > I use lttng-2.5.0 (tools, modules, …) and linux-3.8.13. When I
> try to add context for performance counters I get the following error:
> >> >
> >> >> lttng add-context -u -t perf:cpu:cpu-cycles
> >> > Error: perf:cpu:cpu-cycles: UST invalid context
> >> > Warning: Some command(s) went wrong
> >>
> >> Well i think we will both agree that the help page does not help
> very much.(Should fix that)
> >>
> >> If we go deep down into the code we get the supported context for
> UST domain. :)
> >>
> >> Ust domain support 6 type of context:
> >> LTTNG_EVENT_CONTEXT_VTID
> >> LTTNG_EVENT_CONTEXT_VPID
> >> LTTNG_UST_CONTEXT_VPID
> >> LTTNG_EVENT_CONTEXT_PTHREAD_ID
> >> LTTNG_EVENT_CONTEXT_PROCNAME
> >> LTTNG_EVENT_CONTEXT_IP
> >> LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER
> >>
> >> Well this does help a little ... If we dig a little deeper and
> search around we get more info and see that an enum from
> "./lttng-tools/include/lttng/event.h" lttng_event_context_t maps to another
> one in the lttng-tool side ( context_type in add_context.c)
> >>
> >> *Important Part*
> >> So if we decrypt the macros and functions in add-context.c, we get
> that the following contexts are supported for UST:
> >>
> >> vpid
> >> vtid
> >> pthread_id
> >> procname
> >> ip
> >>
> >> perf:thread:cpu-cycles
> >> perf:thread:cycles
> >> perf:thread:stalled-cycles-frontend
> >> perf:thread:idle-cycles-frontend
> >> perf:thread:stalled-cycles-backend
> >> perf:thread:idle-cycles-backend
> >> perf:thread:instructions
> >> perf:thread:cache-references
> >> perf:thread:cache-misses
> >> perf:thread:branch-instructions
> >> perf:thread:branches
> >> perf:thread:branch-misses
> >> perf:thread:bus-cycles
> >>
> >> perf:thread:L1-dcache
> >> perf:thread:L1-icache
> >> perf:thread:LLC
> >> perf:thread:dTLB
> >> perf:thread:iTLB-loads
> >> perf:thread:iTLB-load-misses
> >> perf:thread:branch-loads
> >> perf:thread:branch-load-misses
> >>
> >> perf:thread:cpu-clock
> >> perf:thread:task-clock
> >> perf:thread:page-fault
> >> perf:thread:faults
> >> perf:thread:major-faults
> >> perf:thread:minor-faults
> >> perf:thread:context-switches
> >> perf:thread:cs
> >> perf:thread:cpu-migrations
> >> perf:thread:migrations
> >> perf:thread:alignment-faults
> >> perf:thread:emulation-faults
> >>
> >> **(TL;DR : perf:cpu:cpu-cycles is not in the list)**
> >>
> >> If you want perf:cpu:cpu-cycles you will need a kernel tracing
> domain.
> >>
> >> Even if it make sense that a ust tracing session cannot touch
> hardware stuff it won’t hurt to be more explicit about it. :).
> >>
> >> >
> >> > We have another machine with 2.5.0 (modules are not installed
> though) and adding perf:cpu:cpu-cycles works fine, but it is always zero in
> results.
> >>
> >> As for this, I cannot explain why lttng-tool does not complain on
> adding the context.
> >> You can open a bug here http://bugs.lttng.org/projects/lttng-tools
> (you will need to create an account and sign in)
> >>
> >> Cheers,
> >> Jonathan
> >>
> >> >
> >> > --
> >> > Cheers,
> >> > Evgeniy
> >> >
> >> >
> >> > _______________________________________________
> >> > lttng-dev mailing list
> >> > lttng-dev at lists.lttng.org <mailto:lttng-dev at lists.lttng.org>
> >> > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >> >
> >>
> >>
> >>
> >>
> >> --
> >> Cheers,
> >> Evgeniy
> >
> >
> > _______________________________________________
> > lttng-dev mailing list
> > lttng-dev at lists.lttng.org
> > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >
>
>
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>
--
Cheers,
Evgeniy
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