bench: flush before shutting down (#8844)

while driving by:
- remove the extra tenant
- remove the extra timelines

implement this by turning the pg_compare to a yielding fixture.

evidence:
https://neon-github-public-dev.s3.amazonaws.com/reports/main/10571779162/index.html#suites/9681106e61a1222669b9d22ab136d07b/3bbe9f007b3ffae1/

test_runner/fixtures/compare_fixtures.py

@@ -102,7 +102,6 @@ class NeonCompare(PgCompare):
         zenbenchmark: NeonBenchmarker,
         neon_simple_env: NeonEnv,
         pg_bin: PgBin,
-        branch_name: str,
     ):
         self.env = neon_simple_env
         self._zenbenchmark = zenbenchmark
@@ -110,16 +109,11 @@ class NeonCompare(PgCompare):
         self.pageserver_http_client = self.env.pageserver.http_client()
 
         # note that neon_simple_env now uses LOCAL_FS remote storage
-
-        # Create tenant
-        tenant_conf: Dict[str, str] = {}
-        self.tenant, _ = self.env.neon_cli.create_tenant(conf=tenant_conf)
-
-        # Create timeline
-        self.timeline = self.env.neon_cli.create_timeline(branch_name, tenant_id=self.tenant)
+        self.tenant = self.env.initial_tenant
+        self.timeline = self.env.initial_timeline
 
         # Start pg
-        self._pg = self.env.endpoints.create_start(branch_name, "main", self.tenant)
+        self._pg = self.env.endpoints.create_start("main", "main", self.tenant)
 
     @property
     def pg(self) -> PgProtocol:
@@ -297,13 +291,11 @@ class RemoteCompare(PgCompare):
 
 @pytest.fixture(scope="function")
 def neon_compare(
-    request: FixtureRequest,
     zenbenchmark: NeonBenchmarker,
     pg_bin: PgBin,
     neon_simple_env: NeonEnv,
 ) -> NeonCompare:
-    branch_name = request.node.name
-    return NeonCompare(zenbenchmark, neon_simple_env, pg_bin, branch_name)
+    return NeonCompare(zenbenchmark, neon_simple_env, pg_bin)
 
 
 @pytest.fixture(scope="function")

test_runner/performance/test_wal_backpressure.py

@@ -2,14 +2,14 @@ import statistics
 import threading
 import time
 import timeit
-from typing import Any, Callable, List
+from typing import Any, Callable, Generator, List
 
 import pytest
 from fixtures.benchmark_fixture import MetricReport, NeonBenchmarker
 from fixtures.common_types import Lsn
 from fixtures.compare_fixtures import NeonCompare, PgCompare, VanillaCompare
 from fixtures.log_helper import log
-from fixtures.neon_fixtures import DEFAULT_BRANCH_NAME, NeonEnvBuilder, PgBin
+from fixtures.neon_fixtures import NeonEnvBuilder, PgBin, flush_ep_to_pageserver
 
 from performance.test_perf_pgbench import get_durations_matrix, get_scales_matrix
 
@@ -20,7 +20,7 @@ from performance.test_perf_pgbench import get_durations_matrix, get_scales_matri
 # For example, to build a `NeonCompare` interface, the corresponding fixture's param should have
 # a format of `neon_{safekeepers_enable_fsync}`.
 # Note that, here "_" is used to separate builder parameters.
-def pg_compare(request) -> PgCompare:
+def pg_compare(request) -> Generator[PgCompare, None, None]:
     x = request.param.split("_")
 
     if x[0] == "vanilla":
@@ -28,7 +28,7 @@ def pg_compare(request) -> PgCompare:
         fixture = request.getfixturevalue("vanilla_compare")
         assert isinstance(fixture, VanillaCompare)
 
-        return fixture
+        yield fixture
     else:
         assert (
             len(x) == 2
@@ -47,10 +47,15 @@ def pg_compare(request) -> PgCompare:
         neon_env_builder.safekeepers_enable_fsync = x[1] == "on"
 
         env = neon_env_builder.init_start()
-        env.neon_cli.create_branch("empty", ancestor_branch_name=DEFAULT_BRANCH_NAME)
 
-        branch_name = request.node.name
-        return NeonCompare(zenbenchmark, env, pg_bin, branch_name)
+        cmp = NeonCompare(zenbenchmark, env, pg_bin)
+
+        yield cmp
+
+        flush_ep_to_pageserver(env, cmp._pg, cmp.tenant, cmp.timeline)
+        env.pageserver.http_client().timeline_checkpoint(
+            cmp.tenant, cmp.timeline, compact=False, wait_until_uploaded=True
+        )
 
 
 def start_heavy_write_workload(env: PgCompare, n_tables: int, scale: int, num_iters: int):