Philippe Gerum wrote: > On Sun, 2009-12-13 at 18:48 +0100, Jan Kiszka wrote: >> Philippe Gerum wrote: >>> On Sat, 2009-12-12 at 22:37 +0100, Jan Kiszka wrote: >>>> Recent moving of ipipe_suspend_domain finally exposed a deeper flaw in >>>> cpu_idle on x86: We failed to check the pipeline log before issuing the >>>> real hlt. This caused IRQ latencies or even drops for Linux, >>>> specifically on SMP. Credits go to plain QEMU whose slow SMP mode caused >>>> ipipe_critical_enter to deadlock frequently enough. >>>> >>>> The first patch of this series fixes this (see below), the second one >>>> simply removes the two useless ipipe_suspend_domain calls. >>>> >>> What your patch does as well, is killing the ability to run low priority >>> domains below the root level. >> Yes, I'm killing the dream. >> >> I heavily doubt that the functions I removed in the second patch ever >> contributed something good to this. It's always the job of the lowest >> domain to issue hardware halt, not of some arbitrary mid-prio domain. >> Moreover, what would be the practical use for such model in the context >> of Linux? > > That is _not_ the point. The point is, when submitting a patch, please > make sure to raise all the concerns it might introduce wrt to changing > the base features. I'm not opposed to make the feature set evolve, but I > don't want this to happen "by mistake".
Just pushed "x86: Drop redundant ipipe_suspend_domain from cpu_idle Allowing domains below root always required more than these calls (Linux would have to give up idle management). And syncing the root domain now takes place in __ipipe_halt_root. So remove these suspension calls." as commit message for the second patch. Is that what you are looking for? Jan
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