Environment variables for controlling profiling

For position sampling only, no environment variables need be set. For sampling with call counting, you need to set the following variables:

• PROFDIR=dir — turn on data collection. The data is stored in a file at dir/pid.program_name. For example, if you run PROFDIR=/tmp ./myapp and the resulting process has PID 12345, the data would be available in /tmp/12345.myapp.
• QCONN_PROFILER=/dev/profiler — turn on data collection and send the data to the /dev/profiler resource manager, which sends it to the IDE. Use this option to attach to a process from the IDE.

When measuring function runtimes, the following environment variables affect application behavior:

• QPROF_START=0|1 — if set to 0, do not start profiling automatically; if set to 1, start profiling automatically (i.e., as soon as the application starts running). The default is 1.
• QPROF_FILE=filepath — enable the profiler data capture process and write the profiling results to the specified filepath. By default, profiling is turned off. To attach the IDE to a running process, you must set this variable to /tmp/program_name.ptrace.
• QPROF_KERNEL_TRACE=1 — use kernel trace events to log function runtimes instead of the profiling instrumentation. When this variable is defined, QPROF_FILE must not be defined.
• QPROF_METHOD=0 — Use ClockCycles() for single-core and realtime clock for multi-core (default).
• QPROF_METHOD=1 — Use ClockCycles() (fast, better resolution) for multi-core; this requires threads to be bound to the same CPU.
• QPROF_METHOD=2 — Use the realtime clock.
• QPROF_METHOD=3 — Use the process time clock.
• QPROF_SIG_STOP_PROFILING=signum — install the stop profiling handler for the signum signal. By default, it isn't installed. The recommended value is 15.
• QPROF_SIG_CONT_PROFILING=signum — install the resume profiling handler for the signum handler. By default, it isn't installed. The recommended value is 16.
• QPROF_HELP=1 — print the profiler help and exit the application.