multiarch support

[povilasv]

I would be keen to add multi arch support for arm/arm64. We might as well do ppc64le / s390x .

For quay you would need to create empty repos like I did for systemd_exporter:

https://quay.io/repository/povilasv/systemd-exporter-linux-amd64
https://quay.io/repository/povilasv/systemd-exporter-linux-s390x
https://quay.io/repository/povilasv/systemd-exporter-linux-ppc64le
https://quay.io/repository/povilasv/systemd-exporter-linux-armv7
https://quay.io/repository/povilasv/systemd-exporter-linux-ppc64le

This is how it looks in quay:

https://quay.io/repository/povilasv/systemd-exporter?tab=tags

What do you think?

FYI I have a working k8s cluster which has arm64/arm nodes in it for testing.

[brancz]

Nice 👍 that would be really awesome!

[povilasv]

FYI cloud drone ci doesn't support docker in docker qemu https://discourse.drone.io/t/run-docker-container-in-docker/5704

So we will have to use workers that are native to that platform (no cross compiling). So we only get arm / arm64 as drone ci cloud supports that. One thing to note is that build queues for arm / arm64 are quite long (builds take 10+ mins)

Right now I have proof of concept in progress:
https://cloud.drone.io/povilasv/conprof/14

I really like drone ci & it looks really good. But If we conisder switching to circle ci we can use https://github.com/prometheus/circleci prometheus orb, which simplifies stuff and get ppc64le / s390x.

Another option is hosting your own drone ci worker, which has docker privilleged enabled.

If we don't care about pc64le / s390x for now, we can work around build queues by just running arm / arm64 builds on merge to master. Otherwise if you are fine to wait 10 mins for a build, it's fine.

WDYT?

[povilasv]

FYI build wait times got way lower, maybe it was just super busy, so we can ignore the wait time issue.

[povilasv]

Finally figured out a way to do it, will test on my cluster and do a PR.

turns out we don't need empty repos, as we just use tags for different architecture images.

[brancz]

Nice 👍. Yeah if we can I would prefer to stick to drone, but no strong opinion. Looking forward to the contribution! :)

[povilasv]

Arm64 works beautifully

[povilasv]

I've made it work on arm (32bit) with the following patch https://github.com/conprof/conprof/pull/45/files#diff-604f4192deea5adf9c159e5f88f64630R54-R69

But CPU usage went crazy high for some reason:

compared to arm64:

Not sure what happened there now it's normal, but I will run arm version for a bit longer and try to reproduce / look at profiles.

[povilasv]

Couldn't reproduce the cpu spike, so I propose to adding it in #49 and if it happens again I will investigate ;)

[povilasv]

Actually I got it again.

When I straced it forever looped in:

sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0
sched_yield()                           = 0

which is go runtime bug in golang/go#38023 , which will be fixed in 1.14.2