Date: Sat, 09 Apr 2011 18:29:23 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Bartosz Fabianowski <freebsd@chillt.de> Cc: Daniel Gerzo <danger@FreeBSD.org>, stable@FreeBSD.org Subject: Re: powerd / cpufreq question Message-ID: <4DA07B53.2090803@FreeBSD.org> In-Reply-To: <4DA06F92.4070702@chillt.de> References: <4D9EEDAF.3020803@rulez.sk> <4D9EF48C.9070907@FreeBSD.org> <e229a6a374fdd5a626c0b777752fef54@rulez.sk> <4D9F2384.5000104@FreeBSD.org> <85cda6f83d328e67a552b2cd5758dbd3@rulez.sk> <4DA06F92.4070702@chillt.de>
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On 09.04.2011 17:39, Bartosz Fabianowski wrote: > I just noticed this thread a day after my own fight with powerd and load > percentages that did not seem to make any sense. > > The patch I came up with is attached. It modifies powerd to use the load > percentage of the busiest core. This reduces the range of values back to > 0%...100% also for multi-core systems. While using maximum of loads can be better then using levels above 100%, it won't properly handle cases of dependent or frequently migrating threads, that are handled now with summary load and levels less then 100%. While existing powerd algorithm is indeed not perfect, it is the only relatively performance-safe, unlike others propositions. I won't argue about adding more algorithms/options to powerd, optimized for handling different situations, but I believe that default should remain safe. > On my Core i7 setup here, the change seems to work well. ... in your specific workload. And you haven't described how you measured system performance to prove that it haven't decreased. -- Alexander Motin
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