Date: Mon, 07 Jul 2008 23:04:10 +0200 From: Kris Kennaway <kris@FreeBSD.org> To: d@delphij.net Cc: freebsd-hackers@freebsd.org, "Murty, Ravi" <ravi.murty@intel.com> Subject: Re: Bug in calcru in he 6.2 and 6.3 kernels Message-ID: <487284CA.4050407@FreeBSD.org> In-Reply-To: <48727E37.30700@delphij.net> References: <AEBCFC23C0E40949B10BA2C224FC61B007A3253D@orsmsx416.amr.corp.intel.com> <48726193.1080807@FreeBSD.org> <48727E37.30700@delphij.net>
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Xin LI wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Kris Kennaway wrote: > | Murty, Ravi wrote: > |> Hello everyone, > |> > |> > |> > |> Finally found what my last problem was. We were running top in a loop > |> and running some workloads that called sched_bind() to bind threads to > |> specific CPUs. The problem was that (and I am using ULE) sched_bind > |> calls a function to notify another CPU of a thread and then mi_switches > |> out of it. Since mi_switch sets the "oncpu" field of the thread to NOCPU > |> and given the thread is still running, calcru would come in and assert > |> the fact that "If I am running I better no be on NOCPU".. It appears > |> that in other parts of the kernel (e.g. forward_signal) this is > |> acceptable (i.e. it is okay to be running and oncpu is NOCPU). > |> > |> > |> Thanks > |> Ravi > | > | Don't use ULE in 6.x, it's broken and will not be fixed. > > Perhaps we should mark it as broken using #error? After all the ULE > changes in 7.x is amazing and we do not want to have users to obtain bad > impressions from the 6.x versions... > > I am not sure but some explicit warning message saying "ULE has been > revamped in FreeBSD 7.x+ and will not be MFC'ed back to 6.x, please use > SCHED_4BSD or upgrade to 7.x." seems to be better than having them to > pursue the mailing list archive... I would agree with this; if you're happy running unstable and broken scheduler code, you're surely able to update to 7.0 and run stable and working scheduler code :) We should run it past re@ first since it's a change to a stable branch, but it's experimental code so I don't see an issue. Kris
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