Messages in this thread | | | Subject | RE: [PATCH] 3/3 Dynamic cpufreq governor and updates to ACPIP-state driver | Date | Tue, 21 Oct 2003 08:47:51 -0700 | From | "Nakajima, Jun" <> |
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> > it's all nice code and such, but I still wonder why this can't be done > by a userland policy daemon. The 2.6 kernel has the infrastructure to > give very detailed information to userspace (eg top etc) about idle > percentages...... I didn't see anything in this driver that couldn't be > done from userspace. >
It's about the frequency of the feedback loop. As we have much lower latency with P-state transitions, the sampling time can be order of millisecond (or shorter if meaningful). A userland daemon can have a high-level policy (preferences, or set of parameters), but it cannot be part of the real feedback loop. If we combine P-state transitions and deeper C-state transitions, the situation is worse with a userland daemon.
Jun
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