12 Jul 2010 mjg59   » (Master)

Power management at Plumbers

I'm running a power management track at the Linux Plumbers Conference again this November. Unlike most conferences which focus on presenting completed work, Plumbers is an opportunity to focus on unsolved problems and throw around as many half-baked solutions as you want in order to try to find one that seems to stick. The suspend/resume problem in Linux is mostly solved[1], which means that it's time for us to focus on runtime power management and quality of service.

This has been an especially interesting year in the field. We've landed the infrastructure for generic runtime power management, glued that into PCI and started implementing that at the driver level. pm_qos is being reworked to improve performance and scalability as we start seeing more drivers that need to express their own constraints. And, of course, we had the wakelock/suspend blockers conversation that didn't end in a terribly satisfactory manner, although Rafael is now working on an implementation that presents equivalent functionality with a different userspace API. Runtime full-system suspend isn't solved yet either - the current cpuidle-based solution doesn't work well on multicore systems. And maybe we could be more aggressive still by looking at reclocking more system components on the fly even if the existing interfaces don't allow that. Do we have all the hooks we need to identify which system resources are being used? Are we doing the best we can in terms of avoiding trading off performance for power savings?

So if you'd like to talk about any of these things, or if there's any other problems that you don't think have been solved yet, head on over to the call for submissions and help make sure that we can make Linux the most power-efficient OS possible.

[1] Yes, some machines are broken, but those tend to be individual weird bugs which we're gradually tracking down rather than fundamental issues in our core code, so they're not really in the scope of Plumbers

Syndicated 2010-07-12 13:53:43 from Matthew Garrett

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