Fixes for dsq_lat.bt

[samuelnair]

• Fix to ensure that we can track dsq id 0
• Cleans up some warnings
• Clean up some maps to avoid them printing out a bunch of output that was not really helpful

[hodgesds]

LGTM, I have another bpftrace script that I'm working on where I just add 1 to the DSQ id to get around handling dsq 0 for zero value map entries. It's kind of annoying but you end up just subtracting 1 when printing and it sort of works.

[htejun]

Longer term, it'd probably make sense to invest a bit more effort into making these scripts more customized to our purposes using e.g. bcc. The default histogram implementation is really not great, DSQ IDs are a lot better printed in hex and so on.

[likewhatevs]

Longer term, it'd probably make sense to invest a bit more effort into making these scripts more customized to our purposes using e.g. bcc. The default histogram implementation is really not great, DSQ IDs are a lot better printed in hex and so on.

I have no idea how practical this is, but I'm gonna take a swing at writing a rust cli that uses small bpf functions to show info these scripts retrieve in a easier to read manner.