Re: 2.2.18Pre Lan Performance Rocks!

Jeff V. Merkey
2000-10-30T09:44:29Z

On Mon, Oct 30, 2000 at 11:50:24AM +0100, Ingo Molnar wrote:
>
> On Mon, 30 Oct 2000, Jeff V. Merkey wrote:
>
> > ds: and es: are both used in copy-to-user and copy-from-user and they
> > get reloaded.
>
> And they all share the same segment descriptor. Whats your point? ES is
> the default target segment for string operations. DS is the default data
> segment. Have you ever profiled how many cycles it takes to do a "mov
> __KERNEL_DS, %es" in entry.S, before making your (ridiculous) claim? I
> have.
>

No. I used a hardware analyzer to show me how many LOCK# assertions it does
invisible to your software tools underneath. Try using EMON to profile,
it gives hardware numbers and let's you watch the cache controllers
issue non-cacheable memory references to fetch the descriptors.

Jeff

> Ingo