Re: [PATCH 0/7] Add RCU-walk support to NFS.

[NeilBrown <neilb@suse.de>]

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On Sun, 13 Jul 2014 22:39:34 -0400 Trond Myklebust
<trond.myklebust@primarydata.com> wrote:

> > I'm certainly happy to try beating on it a bit hard, and can see if I can get
> > access to an 80-core machine that I had a brief play with a while back and do
> > some more testing there.
> 
> As I said, it's not required for merging, but would definitely be an
> interesting test in order to see how it affects NFS performance in
> general. If you have access to a good test setup with an interesting
> workload, then I'd love to see the results of a "before vs after"
> comparison using nfsometer.
> 

I managed to get access to a big machine for a while so I ran nfsometer.
Seemed to run quite well but there are a couple of little issues I might
mention separately.
I didn't let iozone_direct complete because it was taking *forever*.

The results are at http://neil.brown.name/nfsometer_results/

I cannot find a good summary page...

I tested three kernels on the same 80-core (160 if you count hyperthreads)
machine:
   A v3.12  that was installed,
   a vanilla 3.16-rc5,
   and the 3.16-rc5 with my patches.
Some numbers look good, some look strange.
Can you (or someone) have a look?

I also ran my compile-test and graphed some results, which I attach.
This is just 3 kernels, 3.16-rc5 with and without my patches.
I tested both v3 and v4.
I ran the "make" command with "-j" values from 4 to 80 in steps of 4.
The runs lots of compiles of a trivial file but has a very long list of
include directories which are all on NFS and all empty.  So there are lots of
attempts to open non-existent files, and the non-existence is cached early.

As you see, with the "-rcu" very performance is enormously better.  Without
my patches, more concurrency means worse performance.

Thanks,
NeilBrown

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