OTEP: correlating OBI traces to profiles

Signed-off-by: Mattia Meleleo <mattia.meleleo@coralogix.com>

Author: mmat11

oteps/profiles/4855-profiles-obi-correlation.md

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+# Correlating Profiles to OBI Traces
+
+This OTEP introduces a standard communication channel and a specification for correlating profiles to [opentelemetry-ebpf-instrumentation (OBI)](https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation) traces.
+
+<!-- toc -->
+* [Motivation](#motivation)
+* [Design Notes](#design-notes)
+  * [Communication Channel](#communication-channel)
+  * [Data Model](#data-model)
+<!-- toc -->
+
+## Motivation
+
+Currently, OBI traces and profiles operate independently, making it difficult to attribute profiling data to specific traces or spans. By establishing a standard kernel-resident communication channel, this OTEP enables:
+
+- Correlating profiles with their corresponding traces or spans  
+- End-to-end observability workflows without requiring application-level instrumentation  
+
+## Design Notes
+
+### Communication Channel
+
+The communication channel between OBI and the profiler is implemented via an eBPF map pinned at `/sys/fs/bpf/obi_ctx`.  
+
+For both programs to access the map, the `/sys/fs/bpf` filesystem (bpffs) must be mounted and accessible.
+
+### Data Model
+
+As described in the [Profiles Data Model](./0239-profiles-data-model.md), the shared eBPF map uses a minimal structure to store correlation data:
+
+- **Key:** `(u64)pid_tgid`
+- **Value:**  
+
+```c
+struct trace_context {
+    u8 trace_id[16];
+    u8 span_id[8];
+};