Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()

[Hiro Yoshioka <hyoshiok@miraclelinux.com>]

Andrew,

From: Andrew Morton <akpm@osdl.org>
> Andi Kleen <ak@suse.de> wrote:
> >
> > On Friday 02 September 2005 04:08, Andrew Morton wrote:
> > 
> > > I suppose I'll queue it up in -mm for a while, although I'm a bit dubious
> > > about the whole idea...  We'll gain some and we'll lose some - how do we
> > > know it's a net gain?
> > 
> > I suspect it'll gain more than it loses. The only case where it might 
> > not gain is immediately someone reading the data from the page cache again
> > after the write.
> 
> That's a pretty common case - temporary files.
> 
> > But I suppose that's far less frequent than writing the data.
> 
> yup.
> 
> Hiro, could you please send through a summary of the performance testing
> results sometime?  Runtimes rather than oprofile output?

iozone results are

original 2.6.12.4 CPU time = 207.768 sec
cache aware       CPU time = 184.783 sec
(three times run)
184.783/207.768=88.94% (11.06% reduction)

original:
pattern9-0-cpu4-0-08191720/iozone.out:  CPU Utilization: Wall time   45.997    CPU time   64.527    CPU utilization 140.28 %
pattern9-0-cpu4-0-08191741/iozone.out:  CPU Utilization: Wall time   46.878    CPU time   71.933    CPU utilization 153.45 %
pattern9-0-cpu4-0-08191743/iozone.out:  CPU Utilization: Wall time   45.152    CPU time   71.308    CPU utilization 157.93 %

cache awre:
pattern9-0-cpu4-0-09011728/iozone.out:  CPU Utilization: Wall time   44.842    CPU time   62.465    CPU utilization 139.30 %
pattern9-0-cpu4-0-09011731/iozone.out:  CPU Utilization: Wall time   44.718    CPU time   59.273    CPU utilization 132.55 %
pattern9-0-cpu4-0-09011744/iozone.out:  CPU Utilization: Wall time   44.367    CPU time   63.045    CPU utilization 142.10 %

Regards,
  Hiro