Re: Issues with @perf directives in systemtap 3.1 on Ubuntu 16.04LTS

[Geoffrey Blake <geoffrey dot w dot blake at gmail dot com>]

The unmodified perf.stp script is working fine.  The modification I
made was to probe into a library function call by doing:

process("path").library("path").funtion("func") { /* probe code */ }

process("path").library("path").funtion("func").return { /* probe code */ }

This is still yielding the @perf call giving me the same number on
return all the time.
Does @perf not work with library functions?

Thanks,
Geoff Blake

On Mon, Jan 23, 2017 at 9:42 AM, David Smith <dsmith@redhat.com> wrote:
> On 01/23/2017 07:50 AM, Geoffrey Blake wrote:
>> Hi all,
>>
>> I have been trying to make use of the perf.stp example modified for my
>> own program I am trying to profile.  I set the perf.hw probes to be
>> system wide by not supplying a process, but when my other probes
>> trigger and I read the counters with the @perf() directive, the number
>> returned for the counters is always the same junk number (it varies
>> between runs, but never changes during a run).
>>
>> I am not sure what could be going on.  I have tried the systemtap
>> package that ships with Ubuntu 16.04LTS and compiled from the tip of
>> the git repository.  Both versions have the same failure.  Any help
>> would be appreciated on how to debug this further.
>
> Does the unmodified perf.stp example work on your system? How are you
> running your modified example?
>
> --
> David Smith
> dsmith@redhat.com
> Red Hat
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