<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif">Jonathan, et al</div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">Attaching here with logs of the run.</div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">1. Command sequence I ran</div><div class="gmail_default" style="font-family:verdana,sans-serif">2. Console log of commands as I ran them</div><div class="gmail_default" style="font-family:verdana,sans-serif">3. Log of lttng-service daemon <b>lttng-sessiond.txt</b></div><div class="gmail_default" style="font-family:verdana,sans-serif">4. Info about the system, things such as kernel, lttng kernel modules, etc</div><div class="gmail_default" style="font-family:verdana,sans-serif">5. Lastly I tried to build lttng-modules for my kernel 5.9.x. This failed as lacking support for it.</div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">Any help info is appreciated.</div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">Regards,<div>Ramesh</div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Apr 2, 2021 at 11:00 AM <<a href="mailto:lttng-dev-request@lists.lttng.org">lttng-dev-request@lists.lttng.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Send lttng-dev mailing list submissions to<br>
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Today's Topics:<br>
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1. Re: Can't trace function calls (Jonathan Rajotte-Julien)<br>
<br>
<br>
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<br>
Message: 1<br>
Date: Fri, 2 Apr 2021 11:07:19 -0400<br>
From: Jonathan Rajotte-Julien <<a href="mailto:jonathan.rajotte-julien@efficios.com" target="_blank">jonathan.rajotte-julien@efficios.com</a>><br>
To: Ramesh Errabolu <<a href="mailto:ramesh.errabolu@gmail.com" target="_blank">ramesh.errabolu@gmail.com</a>><br>
Cc: <a href="mailto:lttng-dev@lists.lttng.org" target="_blank">lttng-dev@lists.lttng.org</a><br>
Subject: Re: [lttng-dev] Can't trace function calls<br>
Message-ID: <20210402150719.GB79283@joraj-alpa><br>
Content-Type: text/plain; charset=us-ascii<br>
<br>
On Wed, Mar 31, 2021 at 12:55:53PM -0500, Ramesh Errabolu wrote:<br>
> root@RocrLnx23:~/git/compute/out/ubuntu-18.04/18.04/bin# ls ~/ | grep -i ltt<br>
> root@RocrLnx23:~/git/compute/out/ubuntu-18.04/18.04/bin# lttng create<br>
> my-kernel-session --output=~/my-kernel-trace<br>
> Session my-kernel-session created.<br>
> Traces will be output to<br>
> /home/user1/git/compute/out/ubuntu-18.04/18.04/bin/~/my-kernel-trace<br>
> root@RocrLnx23:~/git/compute/out/ubuntu-18.04/18.04/bin# *lttng list<br>
> --kerne*l<br>
> *Error: Unable to list kernel events: Kernel tracer not available*<br>
<br>
Well this would be the first thing to look at.<br>
<br>
First let's deactivate the lttng-sessiond.service installed by the packages.<br>
<br>
systemctl stop lttng-sessiond.service<br>
<br>
You might want to reanable it later.<br>
<br>
> <br>
> root@RocrLnx23:~/git/compute/out/ubuntu-18.04/18.04/bin# ps -ef | grep ltt<br>
> root 1002 1 0 12:16 ? 00:00:00 /usr/bin/lttng-sessiond<br>
> root 1054 1002 0 12:16 ? 00:00:00 */usr/bin/lttng-sessiond*<br>
> root 3145 2861 0 12:51 pts/0 00:00:00 grep --color=auto ltt<br>
> root@RocrLnx23:~/git/compute/out/ubuntu-18.04/18.04/bin#<br>
<br>
Make sure after the systemctl call that no lttng-sessiond process is running.<br>
<br>
Now let's launch a lttng-sessiond by hand with a bit more verbosity. For now<br>
let's stick to the root user.<br>
<br>
# lttng-sessiond -vvv --verbose-consumer -b > /tmp/lttng-sessiond.log 2>&1 <br>
# pkill lttng-sessiond<br>
<br>
Please share the content of /tmp/lttng-sessiond.log using a pasting service<br>
(<a href="http://paste.ubuntu.com" rel="noreferrer" target="_blank">paste.ubuntu.com</a>).<br>
<br>
Also please provide the output of:<br>
<br>
# uname -a<br>
# find /lib/modules/$(uname -r)/ | grep lttng<br>
# dmesg | grep lttng<br>
<br>
<br>
But again, the cyg-profile helper library is meant for Userspace tracing.<br>
<br>
With the app running and having the LD_PRELOAD correctly set, and a sessiond<br>
running.<br>
<br>
# lttng list -u <br>
<br>
If there is nothing, well you can start the application with the following and<br>
share the output of it (make sure to remove any output from your application if<br>
sensitive data is present)<br>
<br>
# LD_PRELOAD=.... LTTNG_UST_DEBUG=1 your_application_here<br>
<br>
Note that debug log will be outputted on stderr.<br>
<br>
Cheers<br>
<br>
-- <br>
Jonathan Rajotte-Julien<br>
EfficiOS<br>
<br>
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