feat(profiling): add conditional jemalloc support for memory allocator testing

Author: vlad-scherbich

riotfile.py

@@ -81,6 +81,8 @@ def select_pys(min_version: str = MIN_PYTHON_VERSION, max_version: str = MAX_PYT
 
 def create_memory_allocator_venvs() -> List[Venv]:
     """Create venv variants for testing different Python memory allocators."""
+    import ctypes
+    
     allocator_configs = [
         {
             "name_suffix": "pymalloc",
@@ -101,9 +103,36 @@ def create_memory_allocator_venvs() -> List[Venv]:
             "name_suffix": "pymalloc-debug",
             "env": {"PYTHONMALLOC": "pymalloc_debug"}, 
             "description": "Python malloc with debug hooks"
-        },
+        }
+    ]
+    
+    # Conditionally add jemalloc variant if the library is available
+    jemalloc_names = [
+        "libjemalloc.so.2",    # Ubuntu/Debian
+        "libjemalloc.so.1",    # Older versions
+        "libjemalloc.so",      # Generic
+        "libjemalloc.dylib",   # macOS (though less common)
     ]
 
+    for lib_name in jemalloc_names:
+        try:
+            # Try to load jemalloc library (OSError is raised if not found)
+            ctypes.CDLL(lib_name)
+
+            allocator_configs.append({
+                "name_suffix": "jemalloc",
+                "env": {
+                    "PYTHONMALLOC": "malloc",
+                    "LD_PRELOAD": lib_name
+                },
+                "description": "jemalloc high-performance allocator"
+            })
+
+            break
+        except (OSError, AttributeError):
+            # Library not found or ctypes issue - try next name
+            continue
+    
     venvs = []
     for config in allocator_configs:
         venvs.append(Venv(
@@ -3348,7 +3377,6 @@ def create_memory_allocator_venvs() -> List[Venv]:
                     pys=select_pys(),
                     pkgs={"uwsgi": "<2.0.30"},
                 ),
-                # Memory allocator testing variants
                 *create_memory_allocator_venvs(),
                 # Python 3.8 + 3.9
                 Venv(