Re: Dom0 starvs DomU

[tg%gmplib.org@localhost (Torbjörn Granlund)]

Greg Troxel <gdt%ir.bbn.com@localhost> writes:

  tg%gmplib.org@localhost (Torbjörn Granlund) writes:
  
  > I'm running NetBSD 7.0 with Xen 4.5, but in my experience this is true
  > for any NetBSD version using any Xen version from pkgsrc
  >
  > When compiling in Dom0 (say, a new xentools version) all DomU's
  > essentially freeze.  I think DomU's which do not touch disk keep
  > running, but guest disk operations seem completely starved by CPU use in
  > Dom0.
  >
  > I suppose this behaviour is well-known.  Are there plans of fixing it.
  >
  > It is worth noticing that Linux+Xen does not show the same problem.
  
  This is not normal and I have not noticed experiencing it with
  netbsd/xen.
  It may just be that I haven't noticed it.
  
  Could you post a recipe to reproduce so others can try?
  
Load the CPU in Dom0, e.g., like this:

  cd usr/pkgsrc/some/package
  make [update|install] clean clean-depends

While that runs, try

  ls -l /usr/bin
  
in some DomU (it doesn't matter if it is NetBSD or some other *nix, if
its is HVM or PV.)

Expect it to give < 1 io-operation/s.

("Don't crunch in Domo then".  Well, I don't.  But upgrading xen to plug
the latest critical issues is quite important...)

-- 
Torbjörn
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