Re: [Qemu-devel] x86 emulated hardware : which make.conf options ?

[Paul Brook]

On Friday 01 April 2005 18:26, Natalia Portillo wrote:
> Use the same optimizations you should use in a real Pentium II.
> You can also enable SSE and SSE2 (but not Pentium III or Pentium 4), as
> QEMU emulates them.

Do you have any facts to substatiate this statement?

The pentium 2, 3, and 4 all support the same core instruction set, the only 
difference being sse and sse2. From the qemu point of view a pentuim3/4 is 
just a pentium2 with sse/sse2.

Qemu emulates the x86 instruction set. It does not implement the 
microarchitecture of a particular implementation. I haven't done any tests, 
but I'd expect the performance characteristics of qemu are significantly 
different to those of a real CPU.

-Os optimizes for code size, not speed. This may be faster than -O2 in some 
cases, but I'd be surprised if that was true in general.

Paul