# Re: \[PATCH V4 0/2\] mm: FAULT\_AROUND\_ORDER patchset performance data for powerpc

- From: Hugh Dickins \<hughd@google.com\>
- Date: 2014-05-20 02:35:47 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2014/05/4256482
- Thread: https://ratatoskr.run/linuxppc-dev/2014/05/4248701/t.md

```text
On Tue, 20 May 2014, Rusty Russell wrote:
> Hugh Dickins [ref] writes:
> >> On Monday 19 May 2014 05:42 AM, Rusty Russell wrote:
> >> > 
> >> > Perhaps we try to generalize from two data points (a slight improvement
> >> > over doing it from 1!), eg:
> >> > 
> >> > /* 4 seems good for 4k-page x86, 0 seems good for 64k page ppc64, so: */
> >> > unsigned int fault_around_order __read_mostly =
> >> >         (16 - PAGE_SHIFT < 0 ? 0 : 16 - PAGE_SHIFT);
> >
> > Rusty's bimodal answer doesn't seem the right starting point to me.
> 
> ?  It's not bimodal, it's graded.  I think you misread?

Yikes, worse than misread, more like I was too rude even to read: sorry!

Hugh
```