Date: Thu, 9 May 2002 09:45:40 +0100 From: Doug Rabson <dfr@nlsystems.com> To: Terry Lambert <tlambert2@mindspring.com>, Andrew Gallatin <gallatin@cs.duke.edu> Cc: John Baldwin <jhb@FreeBSD.ORG>, freebsd-alpha@FreeBSD.ORG Subject: Re: *bsd on srm-less alpha's Message-ID: <200205090945.40777.dfr@nlsystems.com> In-Reply-To: <3CD97001.89254E73@mindspring.com> References: <3CD8BADE.D7D0FC8C@mindspring.com> <15577.7766.160517.751366@grasshopper.cs.duke.edu> <3CD97001.89254E73@mindspring.com>
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On Wednesday 08 May 2002 7:35 pm, Terry Lambert wrote: > Andrew Gallatin wrote: > > He's talking about using MILO, which, at least as of 2.1.13, uses the > > OSF PALcode. What nobody knows is if the PALcode in milo is close > > enough to the "real" OSF PALcode used by the SRM for it to be usable > > by FreeBSD. It certainly seems close, as it has the text "SRM" and > > "OSF" littered all over it. > > > > Now, I've heard various people talk about how we need certain VM > > related PALcode functions that aren't avalable in the MILO palcode, > > However, nobody has mentioned exactly which function this is, and I > > think this might be an urban legend. > > I used to know this. I can describe it in general terms. Linux > has abstracted its translation lookaside so that it can handle it > in software for those processors, like MIPS, which require it. > FreeBSD tries much harder to get the processor to do the work, and > is less abstract. THis means that FreeBSD gets higher performance > on platforms where hardware assitance is possible. Terry, I have no idea what you are talking about here. The TLB on alphas = is=20 always managed by the PALcode. You can't do it anywhere else. The linux=20 kernel code doesn't try to manage TLBs and neither do we. The PALcode TLB= =20 miss handler parses the page tables (which are in standard OSF hierarchic= al=20 form for both FreeBSD and Linux) and inserts the TLB entry. The os doesn'= t=20 play any part in this process. --=20 Doug Rabson=09=09=09=09Mail: dfr@nlsystems.com =09=09=09=09=09Phone: +44 20 8348 6160 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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