3 ms·
4:30 in the linked video or so: it's statically scheduled, in-order, and all opcodes have fixed execution latency. Should be good for real time.
by SAI_Peregrinus 9y ago
4:30 in the linked video or so: it's statically scheduled, in-order, and all opcodes have fixed execution latency. Should be good for real time.
- ema 9y agoThere is still variable timing depending on whether the needed data happens to be in cache or not. Not sure how hard it is to code in such a way that it is predictable what data is gonna be in cache at which times.
- snuxoll 9y agoDRAM access is always going to be variable by nature, though they reduce the problem somewhat by never reordering loads and stores. Stores will always write back to D$1 cache and only hit DRAM when a line needs to be flushed from the last level cache, so assuming your data and code fits in cache you can theoretically have 100% determinism (although all of the specific latency numbers are model-dependent, so just like a traditional DSP you'll have to tune for each target).
- SAI_Peregrinus 9y agoIt's also worth noting that hard real-time systems tend to be custom designed, and often for high-budget products like medical devices or test equipment. So it is probably possible to add a bunch of SRAM to the board, and guaranteed latency to that memory is very easy.