Sometimes "ps -m" options cannot display all processes with timestamp value. crash> ps -m ps: last-run timestamps do not exist in this kernel Usage: ps [-k|-u|-G] [-s] [-p|-c|-t|-[l|m][-C cpu]|-a|-g|-r|-S] [pid | task | command] ... Enter "help ps" for details. This is because output of 'ps -m' depends on task_struct.sched_info.last_arrival. Without CONFIG_SCHED_STAT or CONFIG_SCHED_INFO, 'sched_info.last_arrival' field is not included in task_struct. So we make 'ps -m' option to access 'exec_start' field of sched_entity. where 'exec_start' is task_struct.se.exec_start. With this patch, "ps -m" option works well without CONFIG_SCHED_STAT or CONFIG_SCHED_INFO. The history of CONFIG_SCHED_INFO and CONFIG_SCHED_STAT is as below; - CONFIG_SCHED_INFO: KERNEL_VERSION >= LINUX(4,2,0) - CONFIG_SCHED_STAT: KERNEL_VERSION < LINUX(4,2,0) Signed-off-by: Austin Kim <austindh.kim(a)gmail.com&gt; --- task.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/task.c b/task.c index e6fde74..55e2312 100644 --- a/task.c +++ b/task.c @@ -3565,7 +3565,8 @@ cmd_ps(void) case 'm': if (INVALID_MEMBER(task_struct_last_run) && INVALID_MEMBER(task_struct_timestamp) && - INVALID_MEMBER(sched_info_last_arrival)) { + INVALID_MEMBER(sched_info_last_arrival) && + INVALID_MEMBER(se_exec_start)) { error(INFO, "last-run timestamps do not exist in this kernel\n"); argerrs++; -- 2.20.1