rr numbers each 'event' it records, and you can pass an event number to the gdb 'run' command to tell it to start from that event. Recent 'rr' now also supports

rr numbers each 'event' it records, and you can pass an event number to the gdb 'run' command to tell it to start from that event. Recent 'rr' now also supports the -e option to replay meaning 'start the debug session pointing at the last recorded event, whatever that was'. Details in the usage page: https://github.com/rr-debugger/rr/wiki/Usage https://github.com/rr-debugger/rr/wiki/Usage AIUI you get 'start at an event' basically for free, because 'step backward' is implemented as 'start at the preceding event and then step forward by N', so events are frequent in the trace and the machinery to get to that point without running all the way from the start of the debug session exists anyway. There's some stuff on the website about how this is all implemented, I think.