trace.md

Trace Collection

1. Create a script in the home directory of the web server with the following code:

   echo "Enter the destination folder: "
   read output_folder
   
   echo "Enter the duration of the trace (seconds): "
   read duration
   
   # Create the session
   lttng create my-session --output=$output_folder
   
   # Enable user-space events used to delimit requests
   lttng enable-channel --userspace my-usr-channel
   lttng enable-event --userspace httpd:* --channel=my-usr-channel
   lttng add-context --userspace --channel=my-usr-channel --type=vtid --type=vpid
   
   # Enable all system calls with their arguments
   lttng enable-channel --kernel --subbuf-size=128M --num-subbuf=8 my-kernel-channel
   lttng enable-event --kernel --channel=my-kernel-channel --syscall --all
   lttng add-context --kernel --channel=my-kernel-channel --type=procname
   lttng add-context --kernel --channel=my-kernel-channel --type=pid
   lttng add-context --kernel --channel=my-kernel-channel --type=tid
   
   # Start tracing for the specified duration
   read -p "Press enter to start tracing for $duration s"
   lttng start
   sleep $duration
   lttng stop
   lttng destroy my-session

2. On the web server, execute the installation script:

   bash trace.sh

3. On the web server, press Enter to start tracing

4. On the client, call wrk to send requests:

   ./wrk2/wrk -t8 -c10 -d10s -R100 http://@HOST

5. On the web server, press Enter to stop tracing once wrk has finished