lkml.org 
[lkml]   [2011]   [Jan]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] Prevent users from disabling tickless
From
Date
Le dimanche 02 janvier 2011 à 09:57 +0100, Pavel Machek a écrit :
> Hi!
>
> > Disabling NO_HZ has a serious negative effect on performance -- an extra
> > 70us per I/O. Prevent users from deselecting it.
> >
> > Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
>
> System with fixed HZ is really simpler etc... and 70us per i/o does
> not sound that bad.
>
> Anyway, should not i/o overhead just be fixed?

Also, where are those 70us spent exactly ? Once per clock tick ?

For me, I/O can be an ethernet frame sent or received, and I never
noticed such a delay.

At least, commit message sounds very evasive too me.



--
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/

\
 
 \ /
  Last update: 2011-01-02 10:19    [W:0.093 / U:0.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site