3 ms·
I'm totally flummoxed by the graphs in the "P v E" section. Shouldn't "Total Time" remain constant-ish until the number of threads exceed the number of cores? W
by AlexandrB 3y ago
I'm totally flummoxed by the graphs in the "P v E" section. Shouldn't "Total Time" remain constant-ish until the number of threads exceed the number of cores? Why does time increase linearly with the number of threads on a multi-core system? Or is "Total Time" here "CPU Time" and not wall clock time?
- deleted 3y ago[deleted]
- _a_a_a_ 3y agoYeah. It would make sense if he was running them serially and he sort of says that - "...show a near-perfect linear relationship, with each thread fully occupying one core for a period of 1.3 seconds". But that's not what he says elsewhere - "...so 6 threads will fully load a 6-core P cluster". It really doesn't come together, does it.
- l33t7332273 3y agoThis is definitely the case on other processors. I’ve written a program to detect the number of cores by using that fact.
- renewiltord 3y agoAgreed. I don't understand it either. If running two tasks on two cores takes twice as long, then I'm better off running two tasks one after another on a single core. But if it's CPU time is the interesting result that the increased clock on the E-core when task is assigned means that assigning task to E-core doubles throughput so that two tasks spend equal CPU time as one task? That's interesting but it wasn't clear to me.
- mr_toad 3y agoBy “Total time” on the y axis” I assume that the time for all the threads is summed, otherwise the label “Time” would suffice.