On Mon, October 15, 2007 11:49, Rui Nuno Capela wrote: > On Fri, October 12, 2007 03:04, Steven Rostedt wrote: > >> We are pleased to announce the 2.6.23-rt1 tree, which can be >> downloaded from the location: >> >> http://www.kernel.org/pub/linux/kernel/projects/rt/ >> >> Changes since 2.6.23-rc9-rt2 >> >> - updated to 2.6.23 >> >> - spin_trylock_irqsave macro fix (Sébastien Dugué) >> >> - move rcu_preempt_boost init earlier (Steven Rostedt) >> >> - rt task send IPI condition update (Mike Kravetz) >> > > I am experiencing some highly annoying but intermitent freezing on a > pentium4 2.80G HT/SMT box, when doing normal desktop work with 2.6.23-rt1. > > > The same crippling behavior does not occur on a Core 2 Due T7200 2.0G > SMP, so I suspect it's something due specific to the SMT scheduling > support (Hyper-Threading). But can't tell for sure, obviously :) > I was wrong. After several trials the same behavior also occurs on the Core2 Duo T7200. It just took longer to show its nasty. > The symptoms are noticeable primarily as some X/GUI intermitent freezing, > sometimes only one application, then several and ultimately the whole X > desktop becomes completely unresponsive. It looks like scheduling > problems. There is this hint that switching to a spare console terminal > (via Ctrl+Alt+Fn) might cause later recovery. But its just a question of > some more time for it just happens again and again, one after another, > several applications becoming temporarily frozen and just by luck the > system gets back to normal, probably due to some incidental shake-up :) > but there are other times that nothing seems to help with no alternative > to the power-reset switch. > > I could not find any evidence on dmesg or in the system logs, of any > apparent trouble. No BUGs, no oops, no panics, no nothing. It just > freezes, this and that, now and then. It just makes it all unworkable > and obviously subject to ditching. > > Again, this only happens on this P4/HT box. On a Core2 Duo laptop, with > same 2.6.23-rt1 with the very same kernel configuration, it does not show > any illness and is running quite fine. > False. It used to run fine, until the creeps happen first time :( > Remember one report I had about a similar freezing behavior? Now it's > happening the other way around: the core2 is OK, the pentium4 is KO. > Now it applies to all 2.6.23-rt1 images I could test upon. > One naive suspicion goes like the new rcu-preempt code is to blame, since > I don't remember having this or any other trouble with 2.6.23-rc8-rt1. > Not be sure anymore, but this seems to be still a valid assumption. Just in case someone might try in reproducing this showstopper, the kernel .config is available from here: http://www.rncbc.org/datahub/config-2.6.23-rt1.0 dmesg output as right after init: http://www.rncbc.org/datahub/dmesg-2.6.23-rt1.0 which can't really tell where to look :) Cheers. -- rncbc aka Rui Nuno Capela rncbc@xxxxxxxxx - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
