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Signal handling

SST handles the SIGINT, SIGTERM, SIGUSR1, and SIGUSR2 signals.

Signals are only detected and handled during SST's run phase. Signals sent earlier may be missed. Signals sent later will be ignored.

SIGINT and SIGTERM​

SIGINT and SIGTERM cause SST to initiate an emergency shutdown. It exits the run phase, calls emergencyShutdown() on all components in the simulation, and exits.

SIGUSR1​

Sending SST a SIGUSR1 causes the SST-Core to generate a status message with the current simulation time. The output looks like this.

	CurrentSimCycle:  11090000

In parallel simulations, each parallel context (thread and/or rank) will generate its own message.

SIGUSR2​

Sending SST a SIGUSR2 causes the SST-Core to generate a status message and every component in the simulation is also given the opportunity to generate a status update. SST-Core does this by calling the printStatus() function on each component.

caution

When running SST with OpenMPI, signals sent to the mpirun process are not always handled as expected. This can be avoided by sending the signal directly to one of the SST ranks.

When sent to mpirun:

  • SIGUSR1 and SIGUSR2 signals may be duplicated in SST.
  • SIGINT and SIGTERM are not always delivered to the SST processes so emergency shutdown may not occur before SST is terminated.