On 14.01.2013 01:10, Ian Lepore wrote: > On Sun, 2013-01-13 at 21:36 +0200, Alexander Motin wrote: >> On 13.01.2013 20:09, Marius Strobl wrote: > [...] >>> >>> Uhm, there are no NMIs on sparc64. Does it make sense to bypass this >>> adjustment on sparc64? >> >> If it is not possible or not good to to stop timer during programming, >> there will always be some race window between code execution and timer >> ticking. So some minimal safety range should be reserved. Though it >> probably can be significantly reduced. In case of x86/HPET there is >> additional factor of NMI, that extends race to unpredictable level and >> so makes additional post-read almost mandatory. >> >>>> May be with rereading counter >>>> after programming comparator (same as done for HPET, reading which is >>>> probably much more expensive) this value could be reduced. >>> >>> I see. There are some bigger fish to fry at the moment though :) >> > > Speaking of the HPET code, it seems to me that its restart logic can > fire the same event twice. Is that harmless?
It is much less harmful then not fire and loose interrupt completely, and as result stuck for indefinite time. I have no better ideas, while this seems works well. -- Alexander Motin _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
