Date: Thu, 4 Jul 2013 22:05:35 -0700 From: Kevin Oberman <rkoberman@gmail.com> To: Warren Block <wblock@wonkity.com> Cc: "freebsd-acpi@freebsd.org" <acpi@freebsd.org>, wblock@freebsd.org Subject: Re: Hyper mode for powerd Message-ID: <CAN6yY1s7VukQueOCtV5c9CJyYBuUb6pb89a6Qu8oMCcoU%2BdWLA@mail.gmail.com> In-Reply-To: <alpine.BSF.2.00.1307041955110.10280@wonkity.com> References: <alpine.BSF.2.00.1307041955110.10280@wonkity.com>
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On Thu, Jul 4, 2013 at 7:12 PM, Warren Block <wblock@wonkity.com> wrote: > Attached is a proposed patch for -head that adds a "hyper" mode to powerd. > Instead of slewing like the adaptive modes, this mode drops all the way to > the lowest frequency when the system is idle, and jumps all the way to the > highest frequency when there is any load. > > Subjectively, it seems more responsive for desktop use than hiadaptive > mode. That's hard to benchmark. Power usage is another question. This > mode might use less power than the adaptive modes, but that's also > difficult to benchmark. > > Comments welcome. > > I have not looked at the patch yet, but it should really only use EST and not TC or throttling as many systems, when throttled and put into deep sleep modes (C3 or lower) will hang. Studies have shown (sorry, but since I retired I have lost the papers on the subject) that best power efficiency is when the system is operated at minimum performance when idle and maximum when not, so this is probably a good idea for most any non-mobile system and most mobile system applications. There are cases when you may be willing to pay a response price to keep the battery alive a little longer when performing ongoing activities that don't need large amounts of CPU like listening to music. As I have often pointed out, TCC and throttling were never intended for power management and I strongly recommend that they be disabled. OTOH, deep sleep states are huge winners and should be used to their maximum. EST is a smaller win, but can make a system seem sluggish, especially when added to TCC or throttling. -- R. Kevin Oberman, Network Engineer E-mail: rkoberman@gmail.com
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