From 607aa20e0c0a2c7f473bf7531c907bca616c60f8 Mon Sep 17 00:00:00 2001
From: Pablo Galindo <pablogsal@gmail.com>
Date: Mon, 7 Nov 2022 14:25:35 +0000
Subject: [PATCH] Add benchmark to measure gc collection of a big chain of
 cycles

Signed-off-by: Pablo Galindo <pablogsal@gmail.com>
---
 .../benchmarks/bm_gc_collect/pyproject.toml   |  9 +++
 .../benchmarks/bm_gc_collect/run_benchmark.py | 64 +++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 pyperformance/data-files/benchmarks/bm_gc_collect/pyproject.toml
 create mode 100644 pyperformance/data-files/benchmarks/bm_gc_collect/run_benchmark.py

diff --git a/pyperformance/data-files/benchmarks/bm_gc_collect/pyproject.toml b/pyperformance/data-files/benchmarks/bm_gc_collect/pyproject.toml
new file mode 100644
index 00000000..cb0c4038
--- /dev/null
+++ b/pyperformance/data-files/benchmarks/bm_gc_collect/pyproject.toml
@@ -0,0 +1,9 @@
+[project]
+name = "pyperformance_bm_gc_collect"
+requires-python = ">=3.8"
+dependencies = ["pyperf"]
+urls = {repository = "https://github.com/python/pyperformance"}
+dynamic = ["version"]
+
+[tool.pyperformance]
+name = "gc_collect"
diff --git a/pyperformance/data-files/benchmarks/bm_gc_collect/run_benchmark.py b/pyperformance/data-files/benchmarks/bm_gc_collect/run_benchmark.py
new file mode 100644
index 00000000..db0e4153
--- /dev/null
+++ b/pyperformance/data-files/benchmarks/bm_gc_collect/run_benchmark.py
@@ -0,0 +1,64 @@
+import pyperf
+import gc
+
+CYCLES = 100
+LINKS = 20
+
+
+class Node:
+    def __init__(self):
+        self.next = None
+        self.prev = None
+
+    def link_next(self, next):
+        self.next = next
+        self.next.prev = self
+
+
+def create_cycle(node, n_links):
+    """Create a cycle of n_links nodes, starting with node."""
+
+    if n_links == 0:
+        return
+
+    current = node
+    for i in range(n_links):
+        next_node = Node()
+        current.link_next(next_node)
+        current = next_node
+
+    current.link_next(node)
+
+
+def create_gc_cycles(n_cycles, n_links):
+    """Create n_cycles cycles n_links+1 nodes each."""
+
+    cycles = []
+    for _ in range(n_cycles):
+        node = Node()
+        cycles.append(node)
+        create_cycle(node, n_links)
+    return cycles
+
+
+def benchamark_collection(loops, cycles, links):
+    total_time = 0
+    for _ in range(loops):
+        gc.collect()
+        all_cycles = create_gc_cycles(cycles, links)
+
+        # Main loop to measure
+        del all_cycles
+        t0 = pyperf.perf_counter()
+        collected = gc.collect()
+        total_time += pyperf.perf_counter() - t0
+
+        assert collected >= cycles * (links + 1)
+
+    return total_time
+
+
+if __name__ == "__main__":
+    runner = pyperf.Runner()
+    runner.metadata["description"] = "GC link benchmark"
+    runner.bench_time_func("create_gc_cycles", benchamark_collection, CYCLES, LINKS)