Re: Sleazy FPU optimization

[Matthias Scheler <tron%zhadum.org.uk@localhost>]

On 11 Feb 2008, at 18:43, Joerg Sonnenberger wrote:
> > Linux 2.6.20 and above has an interesting optimization for lazy FPU
> > context saving:
>
> We've been discussing whether or not it is worth to do lazy FPU  
> context
> saving at all. Most programs will use the FPU on i386 anyway, e.g. if
> printf is used. I'm not sure it will actually help.

It is probably also hurts performance on a SMP system if the kernel  
wants to
switch to a thread and its FPU context is on a different CPU.

        Kind regards

--
Matthias Scheler                           http://zhadum.org.uk/