On Tue, Jan 7, 2020 at 10:01 AM Kevin Kofler <kevin.kofler@chello.at> wrote:
Chris Murphy wrote:
> Has zstandard been evaluated? In my testing of images compressed with
> zstd, the CPU hit is cut by more than 50%, and is no longer a
> bottleneck during installations. Image size does increase, although I
> haven't tested mksquashfs block size higher than 256K.

I think increasing the size of the live images, also affecting the download
time and the time to write the image to media (even USB sticks are not
instant), to get a one-time installation speedup is a very bad tradeoff.

Well for the general user, everything is one-time. One download, one write to USB, one install. Saving a minute in one step and adding it to a different step doesn't really matter, it's the same sum overall (unless you pay considerable money for the extra downloaded data, of course). Where it matters is when you do a high amount of operations. And those operations are likely to be installations. Either in some school lab, where you install 20 machines, or, in our very specific example, when you perform automated testing/CI as part of the release process, and perform tens or hundreds of installation every single day. The time difference (and CPU usage difference) saved during installation gets really noticeable in such cases.