2 ms·

̶g̶o̶o̶d̶ ̶l̶i̶n̶k̶ ̶a̶n̶d̶ ̶r̶e̶a̶d̶ ̶b̶u̶t̶ ̶d̶u̶p̶ https://news.ycombinator.com/item?id=34482667 https://news.ycombinator.com/item?id=34482667 My 2 cents,

̶g̶o̶o̶d̶ ̶l̶i̶n̶k̶ ̶a̶n̶d̶ ̶r̶e̶a̶d̶ ̶b̶u̶t̶ ̶d̶u̶p̶ https://news.ycombinator.com/item?id=34482667 https://news.ycombinator.com/item?id=34482667 My 2 cents, I'd like to see Zen 2 merged with some CMT ingenuity for their low power high efficiency branch of cores. Introduce some clustering on one of these Zen 2 CCXs, and arrange this cluster with SMT4 on the FPU side while keeping SMT2 on the integer side. This would be an analogue to the Piledriver family's SMT1/SMT2 int/fpu scheme.

gautamcgoel 4y ago
It's not a dup, that's Part I of the article, this is Part II.
- chaimanmeow 4y ago
  oh thanks and sorry! more to catch up on reading then!! sorry for my oops.
  - pvg 4y ago
    follow-ons (usually) count as dupes so it would be an HN dupe if it had significant discussion but it doesn't so it's not.
deleted 4y ago
[deleted]
Symmetry 4y ago
Clustering certainly has some advantages on low power cores but I wouldn't expect them to go with SMT on lower power cores. Adding SMT doesn't cost much die area but it adds a ton of difficulty to validation. I'd say for little cores you're generally better off with more, smaller, SMT1 cores than fewer, larger SMT2 cores. Where SMT really shines on consumer workloads is that sometimes you only have a few threads, which is why you want it on your big cores. And as an aside, Zen actually has the exact same arrangement of gates in both the bigger and smaller configuration, the smaller one just uses a more consistently small transistor size while the larger one scales transistor size to fanout more aggressively. One place where clustering is being used right now is in Arm's new A510 where two cores share a FPU and L2 but not a front end like the Bulldozer. https://en.wikichip.org/wiki/arm_holdings/microarchitectures/cortex-a510 https://en.wikichip.org/wiki/arm_holdings/microarchitectures...

gautamcgoel 4y ago

It's not a dup, that's Part I of the article, this is Part II.

chaimanmeow 4y ago
oh thanks and sorry! more to catch up on reading then!! sorry for my oops.
- pvg 4y ago
  follow-ons (usually) count as dupes so it would be an HN dupe if it had significant discussion but it doesn't so it's not.

deleted 4y ago

[deleted]

Symmetry 4y ago

Clustering certainly has some advantages on low power cores but I wouldn't expect them to go with SMT on lower power cores. Adding SMT doesn't cost much die area but it adds a ton of difficulty to validation. I'd say for little cores you're generally better off with more, smaller, SMT1 cores than fewer, larger SMT2 cores. Where SMT really shines on consumer workloads is that sometimes you only have a few threads, which is why you want it on your big cores. And as an aside, Zen actually has the exact same arrangement of gates in both the bigger and smaller configuration, the smaller one just uses a more consistently small transistor size while the larger one scales transistor size to fanout more aggressively. One place where clustering is being used right now is in Arm's new A510 where two cores share a FPU and L2 but not a front end like the Bulldozer. https://en.wikichip.org/wiki/arm_holdings/microarchitectures/cortex-a510 https://en.wikichip.org/wiki/arm_holdings/microarchitectures...