ts->usr_time += mtime_since(&td->ru_start.ru_utime,
&td->ru_end.ru_utime);
ts->sys_time += mtime_since(&td->ru_start.ru_stime,
ts->usr_time += mtime_since(&td->ru_start.ru_utime,
&td->ru_end.ru_utime);
ts->sys_time += mtime_since(&td->ru_start.ru_stime,