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Mind linking me some power measurements at same wattage? I didn't even know you could set a power target on Intel or Appl Mx. Well you can disable turbo boost o

Mind linking me some power measurements at same wattage? I didn't even know you could set a power target on Intel or Appl Mx. Well you can disable turbo boost on Intel but even then intel blows over their own marketed TDP by a lot.

jeffbee 3y ago
Intel introduced the "running average power limit" over ten years ago. https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322.html https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322...
- rowanG077 3y ago
  Rapl doesn't allow setting a limit which is always obeyed. You can set PL1 and PL2 limits. But intel CPUs will gladly go over those limits in the short term. For example when running a benchmark. That's why I asked for specific benchmarks which include power measurements. For example: https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247596.0.html https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247... this shows the M2 has a little worse performance compared to the 1360P. But the 1360P requires 2.5x the power to achieve that.
  - Panzer04 3y ago
    Apple’s chips are on better process nodes, which confuses the issue. That being said, you really have to test chips at the same power level to get an idea of performance per watt in a comparison. You can easily double CPU power for only a few hundred MHz or 10-20% extra performance. See https://www.pcworld.com/article/1359352/cool-down-a-deep-dive-into-13900k-power-use-and-efficiency.html https://www.pcworld.com/article/1359352/cool-down-a-deep-div..., which benchmarks chips at different power limits for an example.
    - rowanG077 3y ago
      Yes I agree with you. That doesn't mean this is easy to achieve. With the exception of AMD chips it's unfortunately very hard to simply "benchmark with a fixed power budget".
  - jeffbee 3y ago
    Your model of RAPL's abilities is too limited. "PL1/PL2" is a thing that youtube reviewers have figured out, but it is a part of a larger picture. It does not make sense to discuss them without also discussing the time parameters. RAPL is able to hard-cap the (estimated) peak power consumption. If it lacked this feature, operating them at warehouse scale would be impossible.

jeffbee 3y ago

Intel introduced the "running average power limit" over ten years ago. https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322.html https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322...

rowanG077 3y ago
Rapl doesn't allow setting a limit which is always obeyed. You can set PL1 and PL2 limits. But intel CPUs will gladly go over those limits in the short term. For example when running a benchmark. That's why I asked for specific benchmarks which include power measurements. For example: https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247596.0.html https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247... this shows the M2 has a little worse performance compared to the 1360P. But the 1360P requires 2.5x the power to achieve that.
- Panzer04 3y ago
  Apple’s chips are on better process nodes, which confuses the issue. That being said, you really have to test chips at the same power level to get an idea of performance per watt in a comparison. You can easily double CPU power for only a few hundred MHz or 10-20% extra performance. See https://www.pcworld.com/article/1359352/cool-down-a-deep-dive-into-13900k-power-use-and-efficiency.html https://www.pcworld.com/article/1359352/cool-down-a-deep-div..., which benchmarks chips at different power limits for an example.
  - rowanG077 3y ago
    Yes I agree with you. That doesn't mean this is easy to achieve. With the exception of AMD chips it's unfortunately very hard to simply "benchmark with a fixed power budget".
- jeffbee 3y ago
  Your model of RAPL's abilities is too limited. "PL1/PL2" is a thing that youtube reviewers have figured out, but it is a part of a larger picture. It does not make sense to discuss them without also discussing the time parameters. RAPL is able to hard-cap the (estimated) peak power consumption. If it lacked this feature, operating them at warehouse scale would be impossible.