3 ms·
Have you found benchmarks yet for the second point (DB perf)? I assume by "new cache architecture" you're referring to the switch from a ring to a mesh for L3,
by zbjornson 9y ago
Have you found benchmarks yet for the second point (DB perf)? I assume by "new cache architecture" you're referring to the switch from a ring to a mesh for L3, which was almost necessitated by having more cores in SKL. But at the same time they reduced associativity from 8 to 4 (worse) and made L1-L3 non-inclusive (unsure of the effects yet). They did expand L2 a bit though.
- jandrewrogers 9y agoNo benchmarks yet (and it will be difficult to isolate that effect). The cache structure more closely mirrors the data locality intrinsic in recent high-performance database engines, which don't share data pages across cores and which now commonly use page sizes (256k) that don't fit in L2. The increase in cache size from 256k to 1M is particularly important because it allows you to store multiple pages in L2 which should make a number of multi-page and complex query on single page operations significantly more efficient. Should be great for join kernels. Similarly, the non-inclusive and smaller shared L3 makes more sense in that the amount of state shared across cores is actually pretty small. In short, it redistributes cache resources in a way that is very useful to the way database engines are currently designed.