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Misleading marketing. It has 8 cores and 8 "cores". Hybrid workloads can really kill performance on big.LITTLE architectures.

by bitL 4y ago

kllrnohj 4y ago
Intel's efficient cores are not like the little cores of a big.LITTLE. They are still very potent CPU cores in their own right. We're still talking out-of-order cores & all that jazz ( https://www.anandtech.com/show/16881/a-deep-dive-into-intels-alder-lake-microarchitectures/4 https://www.anandtech.com/show/16881/a-deep-dive-into-intels... ). If you have a multithreaded workload that can actually hammer that many cores, you will get decent scaling out of them ( https://www.pugetsystems.com/labs/articles/Intel-12th-Gen---How-do-P-Cores-and-E-Cores-Compare-2289/ https://www.pugetsystems.com/labs/articles/Intel-12th-Gen---... )
- bitL 4y ago
  Still, it's a "Core" core and "Atom" core together, leading to all kinds of unexpected consanguinities. As with M1 benchmarks, what really suffers is the 20%-80% load area, together with the lack of AVX-512 which 11th gen had that might be a deal breaker to some. Also, having 8 efficiency cores is just silly, if you just want to run background tasks with minimal power consumption, how do 8 cores lead to that?
  - jeffbee 4y ago
    The only thing I can figure out to do on these hybrids is to constrain system junk to the e-cores using a systemd directive, and put all my user session processes on the p-cores in the same fashion. Also necessary to boot with interrupts on the p-cores only, unless you want your nvme and ethernet device performance to be terrible. I'm not sure the complexity is worth it.
  - kllrnohj 4y ago
    There's still 8P cores, so no the 20-80% load area is not suffering. > Also, having 8 efficiency cores is just silly, if you just want to run background tasks with minimal power consumption, how do 8 cores lead to that? Who said efficient cores must only be for low power background tasks? These efficiency cores are small, very small, so Intel can pack a lot of them into the die. And they provide far far bigger returns on multithreaded workloads than SMT does. As in, given a choice between 2 more P cores (so 10P cores total) or these 8 E cores (so 8p+8e), it's a no brainer to go with the 8 E cores. You get larger multithreading returns with a similar die size cost. And the background power efficiency is just a freebie bonus.
    - bitL 4y ago
      Ok, so given you can place 10 P-cores vs 40 E-cores on the same die area by your math, why don't they ship a 40 E-core CPU then? If those little cores are so capable in multi-threading (better than 2P anyway), that would be a big win, no?
      - kllrnohj 4y ago
        Yes exactly https://www.anandtech.com/show/17259/intel-discloses-multigeneration-xeon-scalable-roadmap-new-ecore-only-xeons-in-2024 https://www.anandtech.com/show/17259/intel-discloses-multige...

Misleading marketing. It has 8 cores and 8 "cores". Hybrid workloads can really kill performance on big.LITTLE architectures.

by bitL 4y ago

Misleading marketing. It has 8 cores and 8 "cores". Hybrid workloads can really kill performance on big.LITTLE architectures.

kllrnohj 4y ago

Intel's efficient cores are not like the little cores of a big.LITTLE. They are still very potent CPU cores in their own right. We're still talking out-of-order cores & all that jazz ( https://www.anandtech.com/show/16881/a-deep-dive-into-intels-alder-lake-microarchitectures/4 https://www.anandtech.com/show/16881/a-deep-dive-into-intels... ). If you have a multithreaded workload that can actually hammer that many cores, you will get decent scaling out of them ( https://www.pugetsystems.com/labs/articles/Intel-12th-Gen---How-do-P-Cores-and-E-Cores-Compare-2289/ https://www.pugetsystems.com/labs/articles/Intel-12th-Gen---... )

bitL 4y ago
Still, it's a "Core" core and "Atom" core together, leading to all kinds of unexpected consanguinities. As with M1 benchmarks, what really suffers is the 20%-80% load area, together with the lack of AVX-512 which 11th gen had that might be a deal breaker to some. Also, having 8 efficiency cores is just silly, if you just want to run background tasks with minimal power consumption, how do 8 cores lead to that?
- jeffbee 4y ago
  The only thing I can figure out to do on these hybrids is to constrain system junk to the e-cores using a systemd directive, and put all my user session processes on the p-cores in the same fashion. Also necessary to boot with interrupts on the p-cores only, unless you want your nvme and ethernet device performance to be terrible. I'm not sure the complexity is worth it.
- kllrnohj 4y ago
  There's still 8P cores, so no the 20-80% load area is not suffering. > Also, having 8 efficiency cores is just silly, if you just want to run background tasks with minimal power consumption, how do 8 cores lead to that? Who said efficient cores must only be for low power background tasks? These efficiency cores are small, very small, so Intel can pack a lot of them into the die. And they provide far far bigger returns on multithreaded workloads than SMT does. As in, given a choice between 2 more P cores (so 10P cores total) or these 8 E cores (so 8p+8e), it's a no brainer to go with the 8 E cores. You get larger multithreading returns with a similar die size cost. And the background power efficiency is just a freebie bonus.
  - bitL 4y ago
    Ok, so given you can place 10 P-cores vs 40 E-cores on the same die area by your math, why don't they ship a 40 E-core CPU then? If those little cores are so capable in multi-threading (better than 2P anyway), that would be a big win, no?
    - kllrnohj 4y ago
      Yes exactly https://www.anandtech.com/show/17259/intel-discloses-multigeneration-xeon-scalable-roadmap-new-ecore-only-xeons-in-2024 https://www.anandtech.com/show/17259/intel-discloses-multige...