lkml.org 
[lkml]   [2009]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: lmbench lat_mmap slowdown with CONFIG_PARAVIRT
H. Peter Anvin wrote:
> Right now a number of the call sites contain a huge push/pop sequence
> followed by an indirect call. We can patch in the native code to
> avoid the branch overhead, but the register constraints and icache
> footprint is unchanged.

That's true for the pvops hooks emitted in the .S files, but not so true
for ones in C code (well, there are no explicit push/pops, but the
presence of the call may cause the compiler to generate them).

The .S hooks can definitely be cleaned up, but I don't think that's
germane to Nick's observations that the mm code is showing slowdowns.

J


\
 
 \ /
  Last update: 2009-01-23 01:11    [W:0.080 / U:0.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site