Bug#1149923: vtk9: Please consider reducing --require-mem for guess_concurrency to 3.8G

[Aurelien Jarno]

Source: vtk9
Version: 9.6.2+ds-1
Severity: normal

Hi,

Starting with vtk9 9.6.2+ds-1, the package use guess-concurrency to
limit parallel workers, which is a good move. However on some build
daemons, it significantly increased the build time.

One of the reason is bug#1149922. The other reason is that hardware or
VMs usually use an integer number of GiB for the RAM (and often a power
of 2). There is always a bit of RAM lost (kernel code or data, reserved
memory, ...) and this is enough to get just below the 4G per core.

Would you consider reducing the required memory to 3.8G (guess-concurrency accepts
floating numbers) to account for that?

Thanks
Aurelien