Loading NVBit tool with dlopen() explicitly about nvbit HOT 2 OPEN

More details:
The driver program also does atexit(<pointer to nvbit_at_term)
For the instr_count.so, this is the sequence of events:
After the .so is loaded with dlopen():
the banner "--NVBit ... Loaded--" is output
After a call to nvbit_at_init:
information about various environment variables (INSTR_BEGIN/END ...) is printed.

Output from nvbit_at_term()
Total app instructions: 0

The flow seems to match a run with LD_PRELOAD=inst_count.so except no kernel instrumentation message is seen and the final instruction count is 0.

from nvbit.

libnvbit dlopen()s itself (NULL) in order to find nvbit_* callbacks defined in the tool. I'm loading a tool via LD_LIBRARY_PATH, which may be similar to what you're doing with dlopen(). Anyway, my tool didn't work until I explicitly added a dlopen() (in an __attribute__((constructor))) with the RTLD_GLOBAL flag set. Maybe LD_PRELOAD adds the library to its own DL searches, but LD_LIBRARY_PATH/dlopen() doesn't?

from nvbit.