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MentOS
0.8.0
The Mentoring Operating System
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This structure is used to track the statistics of a process. More...
Public Attributes | |
| int | prio |
| Static execution priority. | |
| time_t | start_runtime |
| Start execution time. | |
| time_t | exec_start |
| Last context switch time. | |
| time_t | exec_runtime |
| Last execution time. | |
| time_t | sum_exec_runtime |
| Overall execution time. | |
| time_t | vruntime |
| Weighted execution time. | |
| time_t | period |
| Expected period of the task. | |
| time_t | deadline |
| Absolute deadline. | |
| time_t | arrivaltime |
| Absolute time of arrival of the task. | |
| bool_t | executed |
| Has already executed. | |
| bool_t | is_periodic |
| Determines if it is a periodic task. | |
| bool_t | is_under_analysis |
| Determines if we need to analyze the WCET of the process. | |
| time_t | next_period |
| Beginning of next period. | |
| time_t | worst_case_exec |
| Worst case execution time. | |
| double | utilization_factor |
| Processor utilization factor. | |
This structure is used to track the statistics of a process.
While the other variables also play a role in CFS decisions'algorithm, vruntime is by far the core variable which needs more attention as to understand the scheduling decision process.
The nice value is a user-space and priority 'prio' is the process's actual priority that use by Linux kernel. In linux system priorities are 0 to 139 in which 0 to 99 for real time and 100 to 139 for users. The nice value range is -20 to +19 where -20 is highest, 0 default and +19 is lowest. relation between nice value and priority is : PR = 20 + NI.
1.9.1