On Tue, Jun 09, 2015 at 09:44:59AM -0700, Andy Lutomirski wrote:
> [1] For those who weren't bitten by this repeatedly, modern Intel CPUs
> (at least Sandy Bridge, anyway) will, by default, detect when all
> cores are in C1 or deeper, think to themselves "wow, the OS selected
> C1 -- it must want a very deep sleep indeed", and put the whole
> package into some kind of deep sleep state. The subsequent wakeup
> takes tens of milliseconds. Doing this in udelay would be awful.
That's a good point. Reportedly, the current MWAITX enters something
between C0 and C1 but the way I understood it, going forward, it will
enter deeper sleep states.
So for shallow C-states, your idle enter/exit latency is low enough but
I'd guess deeper states would be a problem.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
