On Tue, 2013-11-19 at 12:01 +0100, Peter Zijlstra wrote: > What idle function does the core2 use? Something like: > > perf record -a sleep 1; perf report > > Should show you the idle function on top if ran on a mostly idle system. > I would be expecting mwait_idle_with_hints() for core2. And I think I've > covered all paths to it with the right magic, but how knows, these acpi > people never reacted to any of these patches. My Toshiba Satellite lappy does use mwait_idle_with_hints, which works fine unless you boot box with processor.max_cstate=1, which scares hell outta mwait_idle_with_hints, and default_idle is then used. I started tracing it out, and there's a hard coded check (don't recall var name) for cstate 2 being available for some odd reason. The old mwait_idle didn't care, worked fine on Q6600 box for years on end, no idea why the acpi folks made mwait_idle_with_hints get all upset and bail. While tracing out my Q6600 box, it didn't even get to the early probing I had trace_printk laced leading to mwait_idle_with_hints use/fail, then rainy day went away, and I haven't gotten back to it, so default_idle is now all there is for (crusty ole beloved) desktop box. -Mike -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html