In Kernel Switcher: A Solution
summary
Demonstrates a working In Kernel Switcher that presents a pairing A7 and A15 into one logical CPU to the kernel, implements cpufreq masquerading so the governor sees a single wide frequency range, and performs fast core handoffs by powering up the inbound core, synchronizing caches via the CCI and switching contexts in about 20 microseconds. Benchmarks on bbench show a 90% performance at 60% power tradeoff versus an all-A15 system, code is upstreaming and shipping to members.
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chapters (12)
- 0:00What is big.LITTLE?
- 0:59TC2 - ARM's big.LITTLE implementation
- 3:02What is the idea behind big.LITTLE?
- 5:10Heterogeneous Multi Processing (HMP)
- 8:59One possible solution
- 10:15What Linaro has implemented
- 13:00IKS - CPUfreq driver initialisation
- 14:38IKS - Frequencies exposed to CPUFREQ
- 18:58IKS - CPUfreq driver enhancement
- 20:08IKS - Bridging the Chasm
- 33:33IKS - Addition to the Interactive Governor
- 36:13IKS - The Results
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