sudo bpftrace -e '
uprobe:/opt/postgres/master/bin/postgres:vac_update_datfrozenxid {
    @start[pid] = nsecs;
}

uretprobe:/opt/postgres/master/bin/postgres:vac_update_datfrozenxid {
    printf("%d\n", nsecs - @start[pid]);
    delete(@start[pid]);
}
'