feat(profiling)!: add Tracepoint sample type (#1676)

# What does this PR do?

ddprof uses "tracepoint"/"events" as the sample type for hardware counters and perf tracepoint events. The v28 enum-based SampleType API had no equivalent, causing those profiles to fall back to "sample"/"count" and breaking the Datadog backend rendering.

Add `SampleType::Tracepoint` mapping to `ValueType::new("tracepoint", "events")`.

# Motivation

Enable usage of libdatadog sample types in ddprof

# Additional Notes

NA

# How to test the change?

sample_type_round_trip_conversion already passes and automatically covers Tracepoint via EnumIter.

Co-authored-by: erwan.viollet <erwan.viollet@datadoghq.com>

Author: r1viollet

libdd-profiling/src/api/sample_type.rs

@@ -58,6 +58,7 @@ pub enum SampleType {
     ObjectsLegacy,
     RequestTime,
     Sample,
+    Tracepoint,
     SocketReadSize,
     SocketReadSizeSamples,
     SocketReadTime,
@@ -137,6 +138,7 @@ impl From<SampleType> for ValueType<'static> {
             SampleType::ObjectsLegacy => ValueType::new("objects", "count"),
             SampleType::RequestTime => ValueType::new("request-time", "nanoseconds"),
             SampleType::Sample => ValueType::new("sample", "count"),
+            SampleType::Tracepoint => ValueType::new("tracepoint", "events"),
             SampleType::SocketReadSize => ValueType::new("socket-read-size", "bytes"),
             SampleType::SocketReadSizeSamples => {
                 ValueType::new("socket-read-size-samples", "count")
@@ -210,6 +212,7 @@ impl<'a> TryFrom<ValueType<'a>> for SampleType {
             ("objects", "count") => SampleType::ObjectsLegacy,
             ("request-time", "nanoseconds") => SampleType::RequestTime,
             ("sample", "count") => SampleType::Sample,
+            ("tracepoint", "events") => SampleType::Tracepoint,
             ("socket-read-size", "bytes") => SampleType::SocketReadSize,
             ("socket-read-size-samples", "count") => SampleType::SocketReadSizeSamples,
             ("socket-read-time", "nanoseconds") => SampleType::SocketReadTime,

libdd-profiling/src/cxx.rs

@@ -75,6 +75,7 @@ pub mod ffi {
         ObjectsLegacy, // LEGACY: Use InuseObjects instead
         RequestTime,
         Sample,
+        Tracepoint,
         SocketReadSize,
         SocketReadSizeSamples,
         SocketReadTime,
@@ -376,6 +377,7 @@ impl TryFrom<ffi::SampleType> for api::SampleType {
             ffi::SampleType::ObjectsLegacy => api::SampleType::ObjectsLegacy,
             ffi::SampleType::RequestTime => api::SampleType::RequestTime,
             ffi::SampleType::Sample => api::SampleType::Sample,
+            ffi::SampleType::Tracepoint => api::SampleType::Tracepoint,
             ffi::SampleType::SocketReadSize => api::SampleType::SocketReadSize,
             ffi::SampleType::SocketReadSizeSamples => api::SampleType::SocketReadSizeSamples,
             ffi::SampleType::SocketReadTime => api::SampleType::SocketReadTime,