Re: [PATCH v3 3/4] testing: add nfsd-io-bench NFS server benchmark suite

Jeff Layton
2026-04-26T14:12:03Z

On Sun, 2026-04-26 at 05:34 -0700, Andrew Morton wrote:
> On Sun, 26 Apr 2026 07:56:09 -0400 Jeff Layton <jlayton@kernel.org> wrote:
>
> > Add a benchmark suite for testing NFSD I/O mode performance using fio
> > with the libnfs backend against an NFS server on localhost. Tests
> > buffered, dontcache, and direct I/O modes via NFSD debugfs controls.
> >
> > Includes:
> > - fio job files for sequential/random read/write, multi-writer,
> > noisy-neighbor, and latency-sensitive reader workloads
> > - run-benchmarks.sh: orchestrates test matrix with mode switching
> > - parse-results.sh: extracts metrics from fio JSON output
> > - setup-server.sh: configures NFS export for testing
> >
> > Assisted-by: Claude:claude-opus-4-6
>
> OK, question.
>
> > 10 files changed, 1024 insertions(+)
>
> Seems that this code was largely machine-generated. So I assume that
> you're in possession of the scripts/prompts/whatever which were used to
> generate this code.
>
> (Can you please briefly describe the process which you used here?)
>

It's been a while since it generated these, but I think I just asked it
to concoct a set of benchmarks for DONTCACHE writes when that involved
file sizes that were larger than the machine's memory.

I ended up asking it to make some changes (e.g. the mixed-mode test,
and some of the perf stuff), but it seemed to do a reasonable job of
creating it.

> So how are we to maintain this? Will other developers have to go in
> and hack this machine-generated output by hand? Or would it be better
> to provide (in-tree) other developers with the means to regenerate this code,
> presumably using Claude?
>
> IOW, this feels a bit like shipping the .s file without giving us the .c
> file!

As I mentioned in the cover letter, I mostly included this in the
series to demonstrate how this was tested. I'm not sure if the two
benchmark suites are suitable for inclusion. I'm fine with leaving
those two patches out of the merge. I found the testcases useful for
this, but they are indeed AI slop, and I'm not sure they have long-term
value or will be maintainable.
--
Jeff Layton <jlayton@kernel.org>