On Monday 23 February 2009 17:42:44 Colin Guthrie wrote: > 'Twas brillig, and Lennart Poettering at 23/02/09 16:31 did gyre and gimble: > > On Mon, 23.02.09 10:14, Colin Guthrie (gmane at colin.guthr.ie) wrote: > > > >> 'Twas brillig, and Lennart Poettering at 23/02/09 02:05 did gyre and gimble: > >>> OpenSUSE apparently does not enable it. The same is true for > >>> Ubuntu. Same for Debian. Note sure about Mandriva. > >> Here is a (not quite current) grep from my running kernel (it's .27 as > >> .28/.29 both break my intel graphics :( at the moment): > >> > >> $ zgrep -E "HZ|PREEMP" /proc/config.gz > >> CONFIG_PREEMPT_NOTIFIERS=y > >> CONFIG_NO_HZ=y > >> # CONFIG_PREEMPT_NONE is not set > >> CONFIG_PREEMPT_VOLUNTARY=y > >> # CONFIG_PREEMPT is not set > >> # CONFIG_HZ_100 is not set > >> # CONFIG_HZ_250 is not set > >> # CONFIG_HZ_300 is not set > >> CONFIG_HZ_1000=y > >> CONFIG_HZ=1000 > >> CONFIG_MACHZ_WDT=m > >> > >> I'll ask our kernel team why PREEMPT is not on as I've no idea of the > >> consequences. My guess is that it relates to graphics drivers... > > > > The Fedora kernels set PREEMPT_VOLUNTARY as well as it seems. > > Yeah, I asked this of one of our Kernel guys. This is his response, > which seems pretty sensible and balanced to me :) > > > > Well, Lennart actually answered your question ;-) > > Full Preempt used to break several drivers, including graphic, wireless, ... > I've been running a homespun full preempt (and indeed, RT) kernel on Mandriva while using several "dodgy" drivers (nvidia, atheros) for a couple of years without any trouble. On the other hand Ubuntu's non-preempt 300Hz kernel is nothing but trouble... go figure?? Mark
