Date: Sun, 14 Jul 2013 10:31:32 -0600 (MDT) From: Warren Block <wblock@wonkity.com> To: Ian Smith <smithi@nimnet.asn.au> Cc: acpi@freebsd.org, Kevin Oberman <rkoberman@gmail.com>, wblock@freebsd.org Subject: Re: Hyper mode for powerd Message-ID: <alpine.BSF.2.00.1307141008440.61543@wonkity.com> In-Reply-To: <20130714161717.Y12860@sola.nimnet.asn.au> References: <alpine.BSF.2.00.1307041955110.10280@wonkity.com> <20130707003651.Y26496@sola.nimnet.asn.au> <alpine.BSF.2.00.1307062000220.45491@wonkity.com> <20130709145722.U61164@sola.nimnet.asn.au> <alpine.BSF.2.00.1307091058280.46436@wonkity.com> <20130710200113.J23480@sola.nimnet.asn.au> <alpine.BSF.2.00.1307101157460.64697@wonkity.com> <20130714161717.Y12860@sola.nimnet.asn.au>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, 14 Jul 2013, Ian Smith wrote: > What powerd(8) could really use is an update to its man page (or a page > in the handbook, or wiki?) suggesting some reasonable defaults for the > range of hardware nowadays running it. Difficulty: finding "reasonable" defaults. But given the values, I would be willing to add them to that page. > I guess powerd(8) would be also a good place to mention the advantage of > turning off p4tcc and acpi_throttle in loader.conf, as at least a step > towards deprecating their use with powerd? [Kevin, what do you think?] Before that, there should probably be some benchmarks, both for performance and power usage. Those last results I posted left both settings at the default (enabled). I don't know if they do any harm that way. Again, a power usage benchmark would be interesting. A heat level benchmark ought to be possible with the built-in temperature sensors. > > > Hunting away. > > > > Is that a bad thing, though? Effectively, it's just PWM, if you see what I > > mean. > > I do, but to extend that analogy, compare an inverter with squarewave > output to one using a stepped pseudo-sine wave, as most non-pure-sine > inverters do today, much smoother and more efficient too. I don't know > the actual cost of changing freqs via sysctl, but suspect less often and > smaller stepsizes are going to be more efficient and less likely to > shift to a wildly inappropriate freq for load. Perhaps my mechanical > engineering bent worries about wear and tear on the 'gearbox', as it > were, which of course we know to be a non-issue electronically :) I thought that was what Kevin was saying, that shifting to full idle or full throttle was the most efficient. Even if there is a higher cost to larger frequency changes, it may be more than offset by power savings or processing capacity. > > The same periodic daily test as before, again with the first run discarded to > > load the cache. > > > > powerd -a hyper -n hyper -p 50 -v > /tmp/powerd.log > > 977.44 real 47.79 user 238.48 sys > > > > powerd -a hadp -n hadp -p 50 -v > /tmp/powerd.log > > 874.18 real 28.89 user 140.00 sys > > Well hadp here gets the job done more quickly at any rate, both > absolutely and in terms of system and user time. Possibly due to the slower throttling down when the system is detected to be idle. > If you're really burning up to hack on powerd :) a timestamp including > milliseconds on the -v output lines (which might be cut to two lines max > per change) would make it far easier to see what was happening, when .. This really has me thinking more about benchmarks now.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?alpine.BSF.2.00.1307141008440.61543>