5 ms·
Other than obvious stuff like differences in features (AVX512 - although I thought that wasn't even officially supported at one point even though they haven't d
by berkut 4y ago
Other than obvious stuff like differences in features (AVX512 - although I thought that wasn't even officially supported at one point even though they haven't disabled it?) between the P and E cores, how does ARM manage it with big/LITTLE cores? Surely that's similar to a degree (Out of order P cores, in order E cores) to what Intel are attempting?
Are Intel just taking it too far in terms of disparity between the architectures?
- kimixa 4y agoOn an android device I worked on some 5 years ago (so might be out of date) it used a simple cpu mask. Background tasks always used only the little cores, foreground apps always always used only the big cores. I do not believe it was possible for a single app to run threads on both big and little cores. And my understanding is that every arm big.LITTLE combination supported exactly the same ISA and were intentionally 100% binary compatible. For example, you couldn't pair arm A53 little cores (that support only armv8-a) with A75 big cores (which support armv8.2-a)
- londons_explore 4y agoWith some software work, you could pair differing cores. You'd just deliver a signal to a process saying 'youre about to be moved to a different core type, please recheck the capabilities'. Then, you'd have a compatibility shim that emulates unimplemented instructions using traps for software that hadn't yet been rewritten to understand the above signal.
- justincormack 4y agoThere were s small number of phones shipped with differing cores but it did not work well.