Values / timestamp relationship not respected in otlp profiling spec

[brancz]

I just updated Parca to the latest otel profiling spec, and according to the spec:

// A Sample MUST have have at least one values or timestamps_unix_nano entry. If
// both fields are populated, they MUST contain the same number of elements, and
// the elements at the same index MUST refer to the same event.

Specifically the second sentence: If both fields are populated, they MUST contain the same number of elements, and the elements at the same index MUST refer to the same event.

For this reason Parca now has a validation:

if len(s.Value) > 0 && len(s.TimestampsUnixNano) > 0 && len(s.Value) != len(s.TimestampsUnixNano) {
        return fmt.Errorf("sample value length %d does not match sample timestamps length %d", len(s.Value), len(s.TimestampsUnixNano))
}

When I ran the latest commit of the ebpf-profiler against that validation I got this error:

sample value length 1 does not match sample timestamps length 4

It seems like either the ebpf-profiler is not adhereing to the spec, or we need to adjust the spec.

@florianl @rockdaboot @fabled @christos68k

[florianl]

Same as for #700 (comment)

OTel eBPF profiler uses go.opentelemetry.io/collector/pdata/pprofile, which reflects OTel proto v1.7.0 release. The changes you reference to are the most recent one, where there is no release for yet.

[brancz]

I'll also refer to #700 (comment) 😄 .

[florianl]

@brancz maybe it would make sense to test Parca against the latest public release.

[brancz]

I don't really care about compatibility (yet), I'm really doing this to make sure we have up-to-date implementations of the spec.