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发表于 2005-2-3 23:27:16
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Why does this code not work with SMP ?It actually might work (if you remove a one line in systm.h which prevents compilation with SMP). However, you would have a single thread doing the polling, whereas an SMP box might in principle handle concurrently interrupts from different devices.I guess the best answer is that I am not yet sure on whether or not it makes sense to have polling with SMP.
but, according to the following, it seems that polling works pretty good on smp systems.
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Device polling, with SMP?Avleen Vig lists-freebsd at silverwraith.com Thu Nov 20 11:50:42 PST 2003 Previous message: Device polling, with SMP? Next message: Device polling, with SMP? Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] --------------------------------------------------------------------------------On Thu, Nov 20, 2003 at 12:58:58PM -0500, Don Bowman wrote:> > I read Luigi's paper at info.iet.unipi.it/~luigi/polling/ which at the> > end implies that DEVICE_POLLING on an SMP box might not make > > sense - but> > right now for me it would make sense as both CPU's are locked:> > One tries to handle interrupts> > The other tries to manage the application> > > > I could try forcing DEVICE_POLLING to compile as is suggested in that> > URL but I wanted to see if anyone had tried this before.> > The interface is an FXP.> > We use it on em. I just commented out the #error line that> says you can't do it.> device polling in idle doesn't work, and the user/system time> calculation isn't correct, but it works well otherwise.This is pretty much what I wanted to confirm thanks!In which way is the system/user time incorrect? Always, or only underhigh load? what about it is incorrect? My skills are limited but I mighttake a stab at fixing that.-- Avleen VigSystems AdministratorPersonal: www.silverwraith.comEFnet: irc.mindspring.com (Earthlink user access only) |
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