Re: [RFC PATCH 00/19] Cleanup and optimise the page allocator V2

Zhang, Yanmin
2009-03-05T01:57:19Z

On Wed, 2009-03-04 at 10:07 +0100, Nick Piggin wrote:
> On Wed, Mar 04, 2009 at 10:05:07AM +0800, Zhang, Yanmin wrote:
> > On Mon, 2009-03-02 at 11:21 +0000, Mel Gorman wrote:
> > > (Added Ingo as a second scheduler guy as there are queries on tg_shares_up)
> > >
> > > On Fri, Feb 27, 2009 at 04:44:43PM +0800, Lin Ming wrote:
> > > > On Thu, 2009-02-26 at 19:22 +0800, Mel Gorman wrote:
> > > > > In that case, Lin, could I also get the profiles for UDP-U-4K please so I
> > > > > can see how time is being spent and why it might have gotten worse?
> > > >
> > > > I have done the profiling (oltp and UDP-U-4K) with and without your v2
> > > > patches applied to 2.6.29-rc6.
> > > > I also enabled CONFIG_DEBUG_INFO so you can translate address to source
> > > > line with addr2line.
> > > >
> > > > You can download the oprofile data and vmlinux from below link,
> > > > http://www.filefactory.com/file/af2330b/
> > > >
> > >
> > > Perfect, thanks a lot for profiling this. It is a big help in figuring out
> > > how the allocator is actually being used for your workloads.
> > >
> > > The OLTP results had the following things to say about the page allocator.
> > In case we might mislead you guys, I want to clarify that here OLTP is
> > sysbench (oltp)+mysql, not the famous OLTP which needs lots of disks and big
> > memory.
> >
> > Ma Chinang, another Intel guy, does work on the famous OLTP running.
>
> OK, so my comments WRT cache sensitivity probably don't apply here,
> but probably cache hotness of pages coming out of the allocator
> might still be important for this one.
Yes. We need check it.

>
> How many runs are you doing of these tests?
We start sysbench with different thread number, for example, 8 12 16 32 64 128 for
4*4 tigerton, then get an average value in case there might be a scalability issue.

As for this sysbench oltp testing, we reran it for 7 times on tigerton this week and
found the results have fluctuations. Now we could only say there is a trend that
the result with the pathces is a little worse than the one without the patches.

> Do you have a fairly high
> confidence that the changes are significant?
2% isn't significant on sysbench oltp.

yanmin