From: james.harris.1@gmail.com   
      
   On 13/12/2023 15:29, Dan Cross wrote:   
   > In article ,   
   > James Harris   wrote:   
   >> On 23/03/2023 19:49, Dan Cross wrote:   
   >>> In article ,   
   >>> Scott Lurndal  wrote:   
   >>>> cross@spitfire.i.gajendra.net (Dan Cross) writes:   
   >>   
   >> ...   
   >>   
   >>>>>    It was never clear to me   
   >>>>> how a hypervisor could, in general, know the format of the guest   
   >>>>> page tables.  I know the Disco folks had to make some changes to   
   >>>>> Irix to get it to work.   
   >>>>   
   >>>> When I was working on IRIX, I was not fond of either the software   
   >>>> managed TLB, coloring or the Kseg stuff; the MIPS project I worked on was   
   called   
   >>>> Teak and was a distributed version of Irix (eventually cancelled)   
   >>>> for networks of R10k boxes.   
   >>>   
   >>> I get it from a hardware perspective: fewer transistors with a   
   >>> software-managed TLB, but man...so many drawbacks.   
   >>   
   >> Handling a software-managed TLB may be more work, in a sense, but it   
   >> gives an OS developer more control, more feedback, more freedom, and   
   >> perhaps better opportunities for performance gains - as long as the TLB   
   >> is large enough.   
   >   
   > Citation needed.   
   >   
   >> Having the hardware carry out a walk of page tables (the only option if   
   >> the TLB can is updated by hardware) has long seemed to me like a bad   
   >> idea, and it doesn't scale very well as addresses get wider.   
   >   
   > This seems like a claim that isn't going to stand up to close   
   > scrutiny, let alone evidence.   
      
   Is any of that not covered in the reply I've just made to Scott?   
      
      
   --   
   James Harris   
      
   --- SoupGate-Win32 v1.05   
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