| Monitor stall |
| ============= |
| |
| - Name: stall - stalled task monitor |
| - Type: per-task hybrid automaton |
| - Author: Gabriele Monaco <gmonaco@redhat.com> |
| |
| Description |
| ----------- |
| |
| The stalled task (stall) monitor is a sample per-task timed monitor that checks |
| if tasks are scheduled within a defined threshold after they are ready:: |
| |
| | |
| | |
| v |
| #==========================# |
| +-----------------> H dequeued H |
| | #==========================# |
| | | |
| sched_switch_wait | sched_wakeup;reset(clk) |
| | v |
| | +--------------------------+ <+ |
| | | enqueued | | sched_wakeup |
| | | clk < threshold_jiffies | -+ |
| | +--------------------------+ |
| | | ^ |
| | sched_switch_in sched_switch_preempt;reset(clk) |
| | v | |
| | +--------------------------+ |
| +------------------ | running | |
| +--------------------------+ |
| ^ sched_switch_in | |
| | sched_wakeup | |
| +----------------------+ |
| |
| The threshold can be configured as a parameter by either booting with the |
| ``stall.threshold_jiffies=<new value>`` argument or writing a new value to |
| ``/sys/module/stall/parameters/threshold_jiffies``. |
| |
| Specification |
| ------------- |
| Graphviz Dot file in tools/verification/models/stall.dot |
