Environment Variables

Other than the interactions environment variables can have on configuration, there are several standard environment variables that effect the operation of any libmtev application.

• EVENTER_DEBUGGING

  If set to 1 it will enable the debug/eventer log stream.

• MTEV_DWARF

  If set to non-0, dwarf sections will be analyzed to make human readable stacktraces (adding file and line numbers).

• MTEV_JIT_OFF

  If set to 1 it will disable the JIT within the lua module.

• MTEV_JIT_OPT

  If numeric and positive, it be passed numerically to jit.opt.start in the lua module.

• MTEV_RDTSC_REQUIRE_INVARIANT

  If set to 0, this will disable the requirement for an invariant rdtsc for libmtev's "faster time" support.

• MTEV_RDTSC_ENABLE

  If set to 1, this will enable libmtev's "faster time" support if available.

• MTEV_THREAD_BINDING_DISABLE

  If set to 1, threads created via mtev_thread will not be bound to CPUs.

• MTEV_DIAGNOSE_CRASH

  If set to 0, libmtev's internal crash handling code will not be run. If set to 1, will run libmtev's internal crash handling code. If set to a file path for a script or external tool, this will be invoked on a crash with the thread id and process pid as parameters (pid only on non-linux). Use a wrapper script with execution rights and sudoers as needed to give sudo permissions or additional calling parameters when invoking the external tool.

• MTEV_LOG_DEBUG

  If numeric and non-zero, this turns on debug logging for the logging system. This should only be used by developers to debug the logging system itself. These logs all go to stderr.

• MTEV_ASYNCH_CORE_DUMP

  If zero, this disables "asynch core dumps." It forces the monitor process to wait for the child process to leave the process table before attempting to restart it upon crash.

• MTEV_ALTSTACK_SIZE

  A size (in bytes) for the altstack for handling crashes.

• MTEV_WATCHDOG_TIMEOUT

  A timeout observed by the parent monitor. If the child process does not heartbeat from each thread within this number of seconds, the monitor will terminate and restart the child. Non-integral numbers are allowed.