Date: Mon, 21 Jun 2004 00:48:29 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Bruce Evans <bde@zeta.org.au> Cc: FreeBSD current users <current@freebsd.org> Subject: Re: ithread priority question... Message-ID: <Pine.BSF.4.21.0406210044210.69164-100000@InterJet.elischer.org> In-Reply-To: <20040621123607.C8440@gamplex.bde.org>
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On Mon, 21 Jun 2004, Bruce Evans wrote: > On Sun, 20 Jun 2004, Julian Elischer wrote: > > > In swi_add, the priority is multiplied by PPQ. > > This is a layering violation really because PPQ should only be known > > within the scheduler.... but..... "Why multiply by PPQ inthe first > > place?" we are not using the system run queues for interrupt threads. > > > > (PPQ = Priorities Per Queue). > > > > Without this you can remove runq.h from proc.h and include it only in > > the scheduler related files. > > I agree that this makes no sense. Apart from the layering violation, > It seems to just waste priority space. The wastage is not just cosmetic > since someone increased the number of SWIs although there was no room > for expansion. > > Hardware ithread priorities are also separated by 4. The magic number 4 > is encoded in their definitions in priority.h. It's not clear if the 4 is > PPQ or just room for expansion without changing the ABI. Preserving this > ABI doesn't seem very important. seems pointless to me.. It looks to me that at on stage someone was considerring using the standard run-queue code to make interrupt threads runnable. They wanted each interrupt thread to eb on a differen queue and to use the ffs() code to find the next one to run. Feel free to fix it:-) I'm off to bed but I'll look at it again tomorrow if you haven't. > > Bruce >
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