On Fri, 24 Apr 2009, Mathieu Desnoyers wrote: > * Len Brown (lenb@xxxxxxxxxx) wrote: > > Somebody please remind me why we are spending effort to > > maintain the conservative governor instead of deleting it. > > Documentation/cpu-freq/governors.txt > > "The CPUfreq governor "conservative", much like the "ondemand" > governor, sets the CPU depending on the current usage. It differs in > behaviour in that it gracefully increases and decreases the CPU speed > rather than jumping to max speed the moment there is any load on the > CPU. This behaviour more suitable in a battery powered environment." > > So better battery usage seems to be the reason why conservative lives. Yeah, but the question is: is it really better in practice? race-to-idle works better with ondemand. Note: that needs to be answered not just for the current crop of mobile processors, but also for at least stuff as old as the Pentium M and Pentium 4 M. What it _does_ help, is in broken !@#$ hardware that makes a lot of noise due to "singing capacitors" if you use ondemand (because conservative will make less noise as it causes more smooth transitions). NOHZ helped a great deal there, too. I don't know if there are battery environments where a harsher work profile by the CPU are a bad idea. If there are any, conservative will also help there. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
