From bb57fef76b6303c44c51c164c58a0f4f766329d1 Mon Sep 17 00:00:00 2001
From: Nick Ripley <nick.ripley@datadoghq.com>
Date: Wed, 3 Sep 2025 10:14:01 -0400
Subject: [PATCH] chore(profiling): re-accept interval for memory profile
 collector [backport 3.12]

In #14205 we removed the `_interval` parameter for the
`MemoryCollector`.
This was a mistake. Now the memory profile collector thread basically
spins in a tight loop because the interval is 0. Add that parameter
back.

Backports #14276 to the 3.12 branch. This was fixed in 3.12.0 but
somehow didn't make it to 3.12.1 or 3.12.2
---
 ddtrace/profiling/collector/memalloc.py                     | 4 ++++
 ...memalloc-collector-spin-regression-97b4b8093a89c54f.yaml | 6 ++++++
 2 files changed, 10 insertions(+)
 create mode 100644 releasenotes/notes/profiling-fix-memalloc-collector-spin-regression-97b4b8093a89c54f.yaml

diff --git a/ddtrace/profiling/collector/memalloc.py b/ddtrace/profiling/collector/memalloc.py
index ebfb5f0ef2c..72f01b6e842 100644
--- a/ddtrace/profiling/collector/memalloc.py
+++ b/ddtrace/profiling/collector/memalloc.py
@@ -30,13 +30,17 @@
 class MemoryCollector(collector.PeriodicCollector):
     """Memory allocation collector."""
 
+    _DEFAULT_INTERVAL = 0.5
+
     def __init__(
         self,
+        _interval: float = _DEFAULT_INTERVAL,
         max_nframe: Optional[int] = None,
         heap_sample_size: Optional[int] = None,
         ignore_profiler: Optional[bool] = None,
     ):
         super().__init__()
+        self._interval: float = _interval
         # TODO make this dynamic based on the 1. interval and 2. the max number of events allowed in the Recorder
         self.max_nframe: int = max_nframe if max_nframe is not None else config.max_frames
         self.heap_sample_size: int = heap_sample_size if heap_sample_size is not None else config.heap.sample_size
diff --git a/releasenotes/notes/profiling-fix-memalloc-collector-spin-regression-97b4b8093a89c54f.yaml b/releasenotes/notes/profiling-fix-memalloc-collector-spin-regression-97b4b8093a89c54f.yaml
new file mode 100644
index 00000000000..ba2b7d7a9f6
--- /dev/null
+++ b/releasenotes/notes/profiling-fix-memalloc-collector-spin-regression-97b4b8093a89c54f.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    profiling: This fixes a performance regression where the memory profiler's
+    collector thread would spin in a tight loop, consuming nearly a full CPU
+    core.