Author Topic: using bigger CPUs with some cores disabled on Blackbird?  (Read 81 times)

pocock

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using bigger CPUs with some cores disabled on Blackbird?
« on: July 20, 2020, 06:50:51 am »

I started a separate thread about disabling cores in the CPUs in a Talos II

It occurred to me that disabling cores could be a way to reduce CPU power consumption on Blackbird, for example, if you have an 18 core CPU (which is not supported) and you use the operating system to disable 4 cores, leaving just 14 cores, does the power consumption fall within the supported range for the motherboard?

This is probably not a good way to design a new system but if somebody has a spare CPU and they want to temporarily use it in a Blackbird, maybe this would be a useful hack that will reduce the risk of unexpected behavior.
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MPC7500

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Re: using bigger CPUs with some cores disabled on Blackbird?
« Reply #1 on: July 21, 2020, 10:45:07 am »
Haven't tried, but would be interesting if a change in SMT (ppc64_cpu --smt=n) level influences power consumption also.

ClassicHasClass

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Re: using bigger CPUs with some cores disabled on Blackbird?
« Reply #2 on: July 26, 2020, 11:23:25 pm »
A better way might be to manually guard out some of the cores. This is supported by the firmware, even, but I haven't played with doing so intentionally.