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 always managed by the PALcode. You can't do it anywhere else. The linux kernel code doesn't try to manage TLBs and neither do we. The PALcode TLB miss handler parses the page tables (which are in standard OSF hierarchical form for both FreeBSD and Linux) and inserts the TLB entry. The os doesn't play any part in this process. -- Doug Rabson Mail: dfr@nlsystems.com Phone: +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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