From: james.harris.1@gmail.com   
      
   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.   
      
   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.   
      
      
   --   
   James Harris   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)