feat(compute_ctl): Add a basic HTTP API benchmark (#11123)

## Problem

We just had a regression reported at
https://neondb.slack.com/archives/C08EXUJF554/p1741102467515599, which
clearly came with one of the releases. It's not a huge problem yet, but
it's annoying that we cannot quickly attribute it to a specific commit.

## Summary of changes

Add a very simple `compute_ctl` HTTP API benchmark that does 10k
requests to `/status` and `metrics.json` and reports p50 and p99.

---------

Co-authored-by: Peter Bendel <peterbendel@neon.tech>

test_runner/fixtures/endpoint/http.py

@@ -53,6 +53,18 @@ class EndpointHttpClient(requests.Session):
         res.raise_for_status()
         return res.text
 
+    # Current compute status.
+    def status(self):
+        res = self.get(f"http://localhost:{self.external_port}/status")
+        res.raise_for_status()
+        return res.json()
+
+    # Compute startup-related metrics.
+    def metrics_json(self):
+        res = self.get(f"http://localhost:{self.external_port}/metrics.json")
+        res.raise_for_status()
+        return res.json()
+
     def configure_failpoints(self, *args: tuple[str, str]) -> None:
         body: list[dict[str, str]] = []
 

test_runner/performance/test_compute_ctl_api.py

@@ -0,0 +1,64 @@
+from __future__ import annotations
+
+import datetime
+
+import pytest
+from fixtures.benchmark_fixture import MetricReport, NeonBenchmarker
+from fixtures.neon_fixtures import NeonEnv
+
+
+@pytest.mark.timeout(120)
+def test_compute_ctl_api_latencies(
+    neon_simple_env: NeonEnv,
+    zenbenchmark: NeonBenchmarker,
+):
+    """
+    Test compute_ctl HTTP API performance. Do simple GET requests
+    to catch any pathological degradations in the HTTP server.
+    """
+    env = neon_simple_env
+
+    endpoint = env.endpoints.create_start("main")
+    client = endpoint.http_client()
+
+    NUM_REQUESTS = 10000
+
+    status_response_latency_us = []
+    metrics_response_latency_us = []
+
+    for _i in range(NUM_REQUESTS):
+        start_time = datetime.datetime.now()
+        _ = client.status()
+        status_response_latency_us.append((datetime.datetime.now() - start_time).microseconds)
+
+        start_time = datetime.datetime.now()
+        _ = client.metrics_json()
+        metrics_response_latency_us.append((datetime.datetime.now() - start_time).microseconds)
+
+    status_response_latency_us = sorted(status_response_latency_us)
+    metrics_response_latency_us = sorted(metrics_response_latency_us)
+
+    zenbenchmark.record(
+        "status_response_latency_p50_us",
+        status_response_latency_us[len(status_response_latency_us) // 2],
+        "microseconds",
+        MetricReport.LOWER_IS_BETTER,
+    )
+    zenbenchmark.record(
+        "metrics_response_latency_p50_us",
+        metrics_response_latency_us[len(metrics_response_latency_us) // 2],
+        "microseconds",
+        MetricReport.LOWER_IS_BETTER,
+    )
+    zenbenchmark.record(
+        "status_response_latency_p99_us",
+        status_response_latency_us[len(status_response_latency_us) * 99 // 100],
+        "microseconds",
+        MetricReport.LOWER_IS_BETTER,
+    )
+    zenbenchmark.record(
+        "metrics_response_latency_p99_us",
+        metrics_response_latency_us[len(metrics_response_latency_us) * 99 // 100],
+        "microseconds",
+        MetricReport.LOWER_IS_BETTER,
+    )