Building The Default x86_64 Linux Kernel In Just 16 Seconds

[Etherman]

In the single core cpu hdd era it was common to compile with -j2 to minimize waiting for IO.

Maybe a fistfull of extra jobs could help?

[tchiwam]

It's not a matter of "not heard of", but rather trying to be realistic - how many people actually build in tmpfs?

My build sub dirs are always tmpfs since 2004...

[caligula]

I wonder though if most files aren't cached already anyways - the impact may not be as noticeable as some think.

The difference might be noticeable if you have spinning HDD + don't use noatime/relatime. I tried flushing the caches, then compiling three times on SATA SSD, NVMe SSD, and tmpfs. x86 defconfig & tmpfs was the fastest, 2m0,052s on avg. SATA and NVMe SSD were almost as fast here @ 2m0,787s and 2m0,643s on average. Still, I'd expect the I/O perf to have a more significant effect when the compilation is 8 times faster.

[nuetzel]

I wonder though if most files aren't cached already anyways - the impact may not be as noticeable as some think.

So true.

Tried it on my poor Xeon 3470 4c/8t, 24 GB for amd-staging-drm-next.
Only some seconds if any.

[nils_]

I wonder though if most files aren't cached already anyways - the impact may not be as noticeable as some think.

[yokem55]

Yeah, I've had /var/tmp/portage as a tmpfs on my Gentoo boxes for forever. This is a big motivation for getting at least 32gb if ram in them as building chromium nowadays can chew up close to 12gb of disk during the build. And yeah, Zen2 is a monster for compiling code - Yesterday I recompiled everything on my new 3900x Gentoo media server with GCC-9.2 and znver2 (the ebuild showed up in portage yesterday) and ~1100 packages only took about 7hrs to build.

[RavFX]

Meh, that sounds nasty. People usually assume /var/tmp persists over reboot.

https://wiki.gentoo.org/wiki/Portage_TMPDIR_on_tmpfs

It's in Gentoo doc.

[nanonyme]

Michael How many gentooer do you know?

My whole distrib is built in a tmpfs.
All the other gentooer friends I know have configured it like that because... it's faster.

Actually more funny, the only thing that I don't build in a tmpfs, is the kernel, because the tmpfs is /var/tmp (for portage building shenanigans)

Meh, that sounds nasty. People usually assume /var/tmp persists over reboot.

[loganj]

someone here phoronix is really enjoying seeing amd cpu doing a lot better than intel

[bug77]

It would be nice to know how long this takes on NVMe and AHCI drives as well.
But wow!