Date: Tue, 27 Jul 2010 18:16:18 +0300 From: Alexander Motin <mav@FreeBSD.org> To: "Jayachandran C." <c.jayachandran@gmail.com> Cc: Randall Stewart <rrs@freebsd.org>, Neel Natu <neel@freebsd.org>, freebsd-mips@freebsd.org Subject: Re: [RFC] Event timers on MIPS Message-ID: <4C4EF842.5020103@FreeBSD.org> In-Reply-To: <4C4EF398.1050507@FreeBSD.org> References: <4C41A248.8090605@FreeBSD.org> <AANLkTilKYw4UqmfEee9zHGosEDzy4hiFob1d8R9jcB25@mail.gmail.com> <4C41B4CF.6080409@FreeBSD.org> <AANLkTik8_NGm7nKYXT1d1E4Vj6vYQPWHnnLDi78YnvQD@mail.gmail.com> <4C4205CC.6080700@FreeBSD.org> <AANLkTikUpqLeogkqxqWzzejp=7FstHX2wVRWNrYoWGCp@mail.gmail.com> <4C4ED247.80701@FreeBSD.org> <AANLkTiktMt87V5jXV0%2BnagHjpfTkBQ8Fu6CK7HqNXff3@mail.gmail.com> <4C4EF398.1050507@FreeBSD.org>
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Alexander Motin wrote: > Jayachandran C. wrote: >> On Tue, Jul 27, 2010 at 6:04 PM, Alexander Motin <mav@freebsd.org> wrote: >>> Jayachandran C. wrote: >>>> Also, with just the count/compare, I get these print on early mutiuser bootup. >>>> --- >>>> calcru: runtime went backwards from 85936878 usec to 236488 usec for >>>> pid 1286 (rpcbind) >>>> calcru: runtime went backwards from 7158742 usec to 19700 usec for pid >>>> 1285 (nfsiod 0) >>>> calcru: runtime went backwards from 111005442 usec to 305474 usec for >>>> pid 1257 (syslogd) >>>> calcru: runtime went backwards from 10740196 usec to 29555 usec for >>>> pid 1048 (devd) >>>> -- >>>> Did not get much time to investigate, any idea what the cause can be? >>> I think it can easily be result of broken tick_ticker(). >> I'm planning to check-in the attached patch for mips/rmi, I think >> mips/mips would need something similar. > > Looks fine. Does it help? Sorry, after looked again, I've got one question. Why this: + DPCPU_SET(counter_upper, t_upper); + DPCPU_SET(counter_lower_last, t_lower_last); was moved out of the critical section? Due to the per-CPU nature of this function it probably always called inside critical section, so there is no problem I think. But IMHO either critical section calls there are unneeded, or above sets and mips_rd_count() worth moving inside of it. -- Alexander Motin
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