Re: Re: [Bug 350] New: i386 context switch very slow compared to 2.4 due to wrmsr (performance)

Jamie Lokier (jamie@shareable.org)
Wed, 12 Feb 2003 18:23:05 +0000

mika.penttila@kolumbus.fi wrote:
> BTW, why is sysenter supposed to be disabled while in vm86? And if
> it should be disabled (as now in sys_vm86), the next context switch
> back to the vm86 process re-enables it, in load_esp0, right? So what's
> the gain?

I quite misread the code in entry.S at ret_from_int. The comment
"returning to kernel or vm86-space" confused me - of course scheduling
happens in vm86 mode.

(Andi et al., forget anything I've said about CONFIG_PREEMPT problems! :).

-- Jamie
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