Date: Wed, 30 Nov 2016 16:35:20 +0000
From: Mel Gorman <mgorman@techsingularity.net>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>, Michal Hocko <mhocko@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
        Linux-MM <linux-mm@kvack.org>,
        Linux-Kernel <linux-kernel@vger.kernel.org>,
        Rick Jones <rick.jones2@hpe.com>, Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH] mm: page_alloc: High-order per-cpu page allocator v3
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On Wed, Nov 30, 2016 at 04:06:12PM +0100, Jesper Dangaard Brouer wrote:
> > > [...]  
> > > > This is the result from netperf running UDP_STREAM on localhost. It was
> > > > selected on the basis that it is slab-intensive and has been the subject
> > > > of previous SLAB vs SLUB comparisons with the caveat that this is not
> > > > testing between two physical hosts.  
> > > 
> > > I do like you are using a networking test to benchmark this. Looking at
> > > the results, my initial response is that the improvements are basically
> > > too good to be true.
> > >   
> > 
> > FWIW, LKP independently measured the boost to be 23% so it's expected
> > there will be different results depending on exact configuration and CPU.
> 
> Yes, noticed that, nice (which was a SCTP test) 
>  https://lists.01.org/pipermail/lkp/2016-November/005210.html
> 
> It is of-cause great. It is just strange I cannot reproduce it on my
> high-end box, with manual testing. I'll try your test suite and try to
> figure out what is wrong with my setup.
> 

That would be great. I had seen the boost on multiple machines and LKP
verifying it is helpful. 

> 
> > > Can you share how you tested this with netperf and the specific netperf
> > > parameters?   
> > 
> > The mmtests config file used is
> > configs/config-global-dhp__network-netperf-unbound so all details can be
> > extrapolated or reproduced from that.
> 
> I didn't know of mmtests: https://github.com/gormanm/mmtests
> 
> It looks nice and quite comprehensive! :-)
> 

Thanks.

> > > e.g.
> > >  How do you configure the send/recv sizes?  
> > 
> > Static range of sizes specified in the config file.
> 
> I'll figure it out... reading your shell code :-)
> 
> export NETPERF_BUFFER_SIZES=64,128,256,1024,2048,3312,4096,8192,16384
>  https://github.com/gormanm/mmtests/blob/master/configs/config-global-dhp__network-netperf-unbound#L72
> 
> I see you are using netperf 2.4.5 and setting both the send an recv
> size (-- -m and -M) which is fine.
> 

Ok.

> I don't quite get why you are setting the socket recv size (with -- -s
> and -S) to such a small number, size + 256.
> 

Maybe I missed something at the time I wrote that but why would it need
to be larger?

-- 
Mel Gorman
SUSE Labs