Date: Sun, 28 Aug 2005 22:36:38 -0700 From: Nate Lawson <nate@root.org> To: Hajimu UMEMOTO <ume@FreeBSD.org> Cc: Bruno Ducrot <bruno@FreeBSD.org>, cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.sbin/powerd powerd.c Message-ID: <43129EE6.7040608@root.org> In-Reply-To: <yge8xyr5zjq.wl%ume@mahoroba.org> References: <200508240752.j7O7qxep016309@repoman.freebsd.org> <ygemzn7zivx.wl%ume@mahoroba.org> <yge8xyr5zjq.wl%ume@mahoroba.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Hajimu UMEMOTO wrote: >>>>>>On Wed, 24 Aug 2005 20:14:42 +0900 >>>>>>Hajimu UMEMOTO <ume@FreeBSD.org> said: > > ume> It feels too lazy for my laptop. One freq level for decreasing and > ume> two freq level for incresing is comfortable to me. > > Oops, I meant two and four. > Because, my main laptop has double CPU levels than my second laptop. > So, it takes double iteration for transition from highest to lowest or > from lowest to highest. Hello, I am back from vacation. As Kevin and Bruno will attest, I was not happy to go down this path since you can't make everyone happy without a proper predictive algorithm. For small numbers of levels, this algorithm works fine. For large numbers of levels, it can oscillate just as much as the previous algorithm when there is a periodic load. I do not think you should add an option to tune the parameters as this algorithm should be removed as soon as we have something better. I don't want to make it permanent by adding user-visible flags. The right fix is the project that was started by a Summer of Code participant to profile a set of predictive algorithms and choose the best. Some good background info about this is here if someone wants to take up this task: http://wikitest.freebsd.org/moin.cgi/powerd Another mitigating factor is a patch I hope to commit soon that removes levels that aren't useful. The general idea is the same as a recent email from Tijl Coosemans but my approach is different. -- Nate
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?43129EE6.7040608>