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

From: Linus Torvalds (torvalds@transmeta.com)
Date: Wed Feb 12 2003 - 12:24:08 EST


In article <20030212101831.GB10422@bjl1.jlokier.co.uk>,
Jamie Lokier <jamie@shareable.org> wrote:
>
>I meant: the trampoline _stack_ lives in the TSS.
>
>There is no trampoline _code_.

Ahh, ok. That sounds quite doable, and all my complaints go away.

It still leaves the debug exception and NMI issue.

The debug exception case is easy to trigger: use gdb to single-step
through the user-lebel fast system call code, and you _will_ get a debug
exception on the very first kernel instruction (which is also the one
that doesn't have a valid stack).

So anybody want to actually try to implement this?

                Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Feb 15 2003 - 22:00:43 EST