[diffoscope] diffoscope - Excessive memory usage?

[Greg Chabala]

Hello Chris,

I wonder: is the Docker container using a tmpfs?


I don't know if this is a question directed to me, but I ran the command as
shown on https://diffoscope.org/ , just with the ISOs on my desktop, e.g.:

docker run --rm -t -w $(pwd) -v $(pwd):$(pwd):ro
> registry.salsa.debian.org/reproducible-builds/diffoscope image1.iso
> image2.iso


So if I should start it differently to use (or avoid using) a tmpfs, I
wasn't really thinking about it.

Cheers,
Greg

On Thu, Sep 11, 2025 at 8:24 PM Chris Lamb <chris at reproducible-builds.org>
wrote:

> Hello Greg,
>
> > Potentially user error here, but hoping for some ideas.
>
> Well, we don't like to assume user error — or putting it another way,
> diffoscope should make it easy to do the right or expected thing. :)
>
> > I pulled the latest diffoscope container image to compare two 4.7GB DVD
> > ISOs of the same disc. After starting it, it quickly used all 16GB of
> > RAM on the machine, and then another ~8GB of swap.
>
> ISO images are particularly taxing for diffoscope, but it shouldn't be
> hitting memory quite like that. I wonder: is the Docker container
> using a tmpfs? That would certainly exhaust your memory very quickly,
> as the ISO image needs to be extracted before its contents can be
> compared.
>
>
> Regards,
>
> --
>       o
>     ⬋   ⬊      Chris Lamb
>    o     o     reproducible-builds.org 💠
>     ⬊   ⬋
>       o
>
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