Re: Dhrystone -- userland version

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Ted,

On Mon, Jan 9, 2023 at 1:45 AM Theodore Ts'o <tytso@mit.edu> wrote:
> On Sun, Jan 08, 2023 at 07:47:07PM +0100, Pavel Machek wrote:
> > > However, as this is not Linux-specific, how hard can it be to convince
> > > your distro to include https://github.com/qris/dhrystone-deb.git?
> > > Usually, when I have a full userspace available, I just clone the above,
> > > and debuild it myself.
> >
> > Dunno. I'd not solve it if package was in Debian, but it is not.
>
> I would suspect the better long-term solution would be to get the
> package into Debian, since that will be easier for people to use.  I
> suspect the reason why most distros don't include it is because it
> really is a **terrible** benchmark for most use cases.

My use case is verifying the CPU core clock rate when working on
the clock driver and/or cpufreq.  I can easily measure e.g. SPI or
UART clock rates
externally, but not CPU core clock rates.

> (I'm not even convinced that using it to try to auto-tune the schedule
> by including a random dhrystone number in a device tree is reallty all
> that useful, but hey, I'm not a scheduler expert.)

I leave that to the scheduler people, too ;-)

> So I took a quick look at dhrystone-deb.git, as well as the original
> version of the Dhrystone source code at [1], and I do see huge red
> flag show-stopper that would prevent it from getting it into Debian.
>
> There are no copyright license notices anywhere in the source code,
> and from what I can tell, it was originally published in ACM's SIGPLAN
> Notices --- which even today is behind a paywall, so I presume it's
> under an ACM copyright.

Note that the version published by ACM was the original ADA version...

> Which makes me wonder --- did someone get copyright clearance from ACM
> and/or the original authors before this was published in a linux git
> tree?  And if not, we should get this clarified before someone sends a
> pull request to Linus with a potential copyright licensing problem.

I used "GPL-2.0-only OR BSD-2-Clause"[1], as the latter is what FreeBSD
uses, now augmented with calls into Linux-specific code.

Contacting the original author is no longer possible, unfortunately[3].
I don't know if Rick Richardson is still around.

> However, there are people who use the Linux kernel who are much
> touchier about copyright concerns, so if we can't build a Linux kernel
> without including lib/dhrystone.c, and we don't have copyright
> permission from ACM, I suspect some corporate lawyers would
> be.... uneasy.

Chromium hosts the Dhrystone benchmark as part of the LLVM testsuite,
under the LLVM license[4].  The Fuego Test System says MIT[5].

[1] https://lore.kernel.org/all/CAMuHMdXVkdmnKDobfZHkk+Lxradq238wAcaLOyW-cmS7J3MS4g@mail.gmail.com
[2] https://www.freshports.org/benchmarks/dhrystone/
[3] https://www.spec.org/spec/memories/reinhold/
[4] https://chromium.googlesource.com/native_client/pnacl-llvm-testsuite/+/c5be109f343430594ecec866dfa6d9833b921e1e/SingleSource/Benchmarks/Dhrystone/LICENSE.TXT
[5] http://fuegotest.org/server/Benchmark.Dhrystone

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds