lkml.org 
[lkml]   [1998]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] i386 entry.S alignment tweak


On Fri, 11 Dec 1998, MOLNAR Ingo wrote:
>
> either we align system_call, or we align ret_from_sys_call, we cant have
> both. Given that ret_from_sys_call is shared with IRQ handlers, it's
> better performance-wise to align that one.

Don't bother about IRQ handlers. Either they take a cache miss or they
don't, it's not something we should worry about: if the interrupts happen
so much that it matters then the system is not very usable anyway for
completely other reasons than one cache miss.

It's only system calls we really want to have minimal cache footprints and
good behaviour - ie the entrypoint should be aligned, and the mid-way
point should _not_ have extra nop's to align it. System calls are
critical, and can often be entered with cold caches.

Linus


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

\
 
 \ /
  Last update: 2005-03-22 13:46    [W:0.066 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site