Re: i386 PDA patches use of %gs

[Ingo Molnar]

* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> [...]  The basic inner loop is:
> 
> 	push %segreg
> 	mov  %selectorreg, %segreg
> 	add  $1,%segreg:offset	# use the segment register
> 	pop  %segreg

well, the most important thing i believe you didnt test: the effect of 
mixing two descriptors on the _same_ selector: one %gs selector value 
loaded and used by glibc, and another %gs selector value loaded and used 
by the kernel, intermixed. It's the mixing that causes the descriptor 
cache reload. (unless i missed some detail about your testcase)

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