From mboxrd@z Thu Jan 1 00:00:00 1970 From: jonathan.rajotte-julien@efficios.com (Jonathan Rajotte-Julien) Date: Wed, 13 May 2020 11:33:12 -0400 Subject: [lttng-dev] Need Help In trace generation for malloc(), free() calls etc In-Reply-To: References: Message-ID: <20200513153312.GA2381108@joraj-alpa> Hi Abhinav, Please refrain from using screenshots when pastebin could be used (code, commands, etc). On Wed, May 13, 2020 at 10:29:22AM +0530, Abhinav Ranjan via lttng-dev wrote: > Hello Sir, > I am Abhinav from India. > *Kindly Ignore the previous email.* > Actually I am very new to the Embedded System Engineering profession. In > fact I have been asked to do an independent project to instrumenting a c > application using LLTng concept to find/trace calls to malloc(), free() > calls. In fact i tried capturing the same as below steps but didn't > understand why after using LD_PRELOAD also malloc() and free() calls were > not traced. I am not sure whether my app was correct!! > > I followed the steps provided to create executable using -lltng-ust -ldl > 2.I executed it as: LD_PRELOAD=liblttng-ust-libc-wrapper.so ./executable > (initially as ./exe arg)) > 3. Then I followed commands to create , capture the events. and destroyed > it. Based on the screenshot "creation_trace.PNG", it seems that you enable only the event you defined (malloc_trace_investigation). Keep in mind that the libc wrapper defines its own tracepoints and tracepoint providers. It the case of the libc wrapper the tracepoint providers available are: lttng_ust_libc and lttng_ust_pthread Both have multiple tracepoints defined under them. Hence what you want for you experiment is something like this: lttng enable-event -u malloc_trace:investigation lttng enable-event -u 'lttng_ust_libc:*' Keep in mind that you can list the events available for a currently running app using: lttng list -u The app must be running for the listing work. Cheers.