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The chip image surprised me: where's the L3 cache? On previous generations, L3 cache was a significant amount of real estate. Is it no longer shared between c
by 3JPLW 6y ago
The chip image surprised me: where's the L3 cache? On previous generations, L3 cache was a significant amount of real estate. Is it no longer shared between cores?
- icegreentea2 6y agoL3 cache is under the "Coherent Fabric" block (it's the 12MB Last Level Cache thing).
- 3JPLW 6y agoI'm talking about this image: https://images.anandtech.com/doci/16063/474551355-Intel-Blueprint-Series-11th-Gen-Intel-Core-Processors-pdf-page-034.jpg https://images.anandtech.com/doci/16063/474551355-Intel-Blue... I don't see any coherent fabric blocks — what looks like large cache sections to my eyes are entirely inside the "Core" blocks. Maybe they're just not drawn correctly. Here are some much older i7s, for example: https://www.cs.uaf.edu/2009/fall/cs441/proj1/russell/images/df94g6m6_4gxrw53gk_b.png https://www.cs.uaf.edu/2009/fall/cs441/proj1/russell/images/... https://www.notebookcheck.net/fileadmin/_migrated/pics/Core_I7_LGA_2011_Die-1.jpg https://www.notebookcheck.net/fileadmin/_migrated/pics/Core_...
- wmf 6y agoThe labeling on that image is... approximate. You can see the orange L3 blocks inside the area labeled as cores and it's still shared.
- 3JPLW 6y ago> it's still shared Right, that was really my main question: besides the labeling (which is of course approximate), the positioning sure looks like each core would have its own "favorite" section of the cache. And being shared, it seems like this could make for some interesting performance behaviors. Ah, interesting, this topology was introduced with Sandy Bridge. I'm just out of date: https://www.anandtech.com/show/3922/intels-sandy-bridge-architecture-exposed/4 https://www.anandtech.com/show/3922/intels-sandy-bridge-arch...
- icegreentea2 6y agoYeah, you need something like that to scale to large core counts, and especially if you wanna pull off some chiplet goodness (like AMD did with Ryzen). I think that's why it got lumped with the Fabric Interconnect layer in one of the block diagrams.
- icegreentea2 6y agoI found another annotated shot of your anandtech shot: https://cdn.wccftech.com/wp-content/uploads/2020/08/Intel-Tiger-Lake-11th-Gen-Mobile-CPU-10nm-Die-Shot_2.jpg https://cdn.wccftech.com/wp-content/uploads/2020/08/Intel-Ti... Looks like ya, the L3 cache is "inside" the core blocks.