Re: [Qemu-devel] Qemu varying performance

[Torbjorn Granlund <tg@gmplib.org>]

"Edgar E. Iglesias" <edgar.iglesias@gmail.com> writes:

  > But running Debian's 64-bit kernel vmlinux-2.6.32-5-5kc-malta under
  > qemu-system-mips64 consumes 100% on the host system, whether the guest
  > is idle or busy.  (And for qemu-system-mips64el, the same is true for the
  > corresponding 64-bit el kernel.)

  Hi, It could be any of them or both. You'll have to dig a bit deeper and
  see if WAIT insns are beeing issued and if QEMU is successfully decoding
  them etc.
  
Thanks for this advice!

I naively ran 'objdump -dw' on the kernel, looked for wait, and thanks
to the naming of kernel idle loop functions, was able to make educated
guesses about which processors would be fed the 'wait' instruction.

The feeble conclusion made, that passing '-cpu 5Kc' to
qemu-system-mips64{el,} would help, turned out to be correct--now my
mips64 systems uses insignificant host CPU when they idle.

-- 
Torbjörn