Re: Utility of PV on non-obsolete hardware

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

"Mathew, Cherry G." <cherry%zyx.in@localhost> writes:

  That's a good point - I'm surprised about the I/o performance though -
  were you using virtio ?

I was not.

I lamely tried to enable virtio for networking, but got an error
message.  I didn't try virtio for disk ops.

The compile test I performed reads each source over NFS and writes
objects to a local disk.  The local disk is provided via a Gentoo Dom0
through LVM.  So there is a fair bit of networking and disk ops going
on, but still not very much compared to the CPU used by the compiler.

The speed difference is huge between different OSes.  Here is a table
for the main builds on the Goldmont system:

   glmfbsd64v10.gmplib.org-stat:64.txt   214
   glmfbsd64v93.gmplib.org-stat:64.txt   234
   glmfbsd64v11.gmplib.org-stat:64.txt   305
   glmfbsd64v12.gmplib.org-stat:64.txt   308
   glmnbsd64v80.gmplib.org-stat:64.txt   329
    glmdeb64v10.gmplib.org-stat:64.txt   335
     glmdeb64v8.gmplib.org-stat:64.txt   341
     glmdeb64v7.gmplib.org-stat:64.txt   347
     glmdeb64v9.gmplib.org-stat:64.txt   366
    glmgentoo64.gmplib.org-stat:64.txt   395
   glmnbsd64v61.gmplib.org-stat:64.txt   498
   glmnbsd64v70.gmplib.org-stat:64.txt   502
   glmnbsd64v71.gmplib.org-stat:64.txt   508
   glmnbsd64v72.gmplib.org-stat:64.txt   509
            glm.gmplib.org-stat:64.txt   541

(The system naming might seem awkward, but I think it's pretty clear
what the abbreviations mean.)

Usual caveat: While all systems build exactly the same sources, the
systems run different compilers as well as /bin/sh.

The slowest systems all use PV.  The system glm.gmplib.org is the Dom0,
which is not (yet) under PVH.  Then comes all PV NetBSD systems.

Some of the apparent speedup with HVM is also a slowdown in the Dom0, as
its qemu processes use up a fair amount of CPU.

   I'm about 70% of the way enabling PVHVM for domU - we have PoC but
  needs a bit more debugging etc. Also looking at non PV Dom0 solutions.

That's good news!  That should help to lower the Dom0 load.

Are there also plans for PVH?

-- 
Torbjörn
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