4 ms·
There is definitely an argument to be made regarding uops that just because the vector width of the interface doubled, the hardware resouces need not have doubl
by incrudible 4y ago
There is definitely an argument to be made regarding uops that just because the vector width of the interface doubled, the hardware resouces need not have doubled as well. AVX512 originally came from KNL accelerators, which were designed for more specific purposes.
- Const-me 4y agoI agree. And these resources are not even limited to execution units inside cores. Another one is bandwidth. On computers with dual-channel DDR4, aligned SSE vectors are delivered from main memory with a single transaction. For ideal scaling from SSE, AVX512 would need octa-channel DDR4, and 4x as much caches. Another one is waste heat. On modern processors, sustained performance is often limited by thermals. For ideal scaling, AVX512 would need twice as much cooling compared to AVX.