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Two questions about RTX51 Tiny performance (Note: I have Round Robin disabled): 1) In the Overview section of the User's Guide, it lists context switch time as "100..700 cycles". In terms of execution time, that's like saying "bigger than a bread basket, smaller than a mountain". Can anyone expound upon the context switch time a bit? What factors contribute to this? 2) With round-robbin disabled, how many cycles does the RTX timer interrupt consume? I'm not taking about the interrupt latency the manual lists, rather cycles (min/max range thereof) the timer interrupt itself consumes. ???
1) In the Overview section of the User's Guide, it lists context switch time as "100..700 cycles". In terms of execution time, that's like saying "bigger than a bread basket, smaller than a mountain". Can anyone expound upon the context switch time a bit? What factors contribute to this? RTX51 Tiny manages all task stacks in IDATA memory. When switching to a new task, the kernel moves the other task stack out of the way. This may be fast (if there are few tasks with short stacks) or it may be slow ( is there are many tasks with large stacks). Refer to the following manual page for a description of how this works. http://www.keil.com/support/man/docs/tr51/tr51_stackmgmt.htm I think this is the main contributor to task switch times. 2) With round-robbin disabled, how many cycles does the RTX timer interrupt consume? I'm not taking about the interrupt latency the manual lists, rather cycles (min/max range thereof) the timer interrupt itself consumes. That I don't know. However, I believe it will take less because most (if not all) functionality is there even with round-robin enabled. Jon