Re: [uml-devel] Multi-threaded applications and floating point registers

[Stanislav Meduna <stano@meduna.org>]

Ingo van Lil wrote:

> I'm experiencing some weird problems with a multi-threaded application 
> I'm working on: A function which uses nothing but a single input value, 
> a few constants and a couple of floating point operations returns wrong 
> results from time to time. The application uses multiple threads, and 
> we're suspecting that the FPU state isn't properly saved and restored 
> when switching between threads within a process.

I had a similar problem between processes a few months ago,
I also posted an example, unfortunately with no resolution
nor further inquiries from the developers. I suspect the skas3
patch does not get much attention now...

Try to run the guest with mode=skas0 - in my case it eliminated
the problem and the guest is running for months without a hiccup.
If your problem is the same, it will probably help as well.

> We're suspecting that the problem has been introduced by the
> patch [1] to stop saving the process FP state which has been
> applied just before 2.6.24-rc1.

In my case it was reproducible with 2.6.23.17 as well.

Regards
-- 
                                      Stano

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