From 3ff2e7c846a23deec74f96aa7dcfca7f575de698 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Fri, 26 Sep 2025 12:16:04 -0700
Subject: [PATCH 1/4] Run cudf-polars wheels unit tests with more than 1
 process

---
 ci/run_cudf_polars_pytests.sh | 3 +++
 ci/test_python_other.sh       | 2 +-
 ci/test_wheel_cudf_polars.sh  | 2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/ci/run_cudf_polars_pytests.sh b/ci/run_cudf_polars_pytests.sh
index 304573d6a85..e7a9837cd66 100755
--- a/ci/run_cudf_polars_pytests.sh
+++ b/ci/run_cudf_polars_pytests.sh
@@ -18,7 +18,10 @@ python -m pytest --cache-clear "$@" tests --executor streaming
 python -m pytest --cache-clear "$@" tests --executor streaming --blocksize-mode small
 
 # Run experimental tests with Distributed cluster
+# Runtime in CI tends to increase when running these tests with multiple processes.
+# https://github.com/rapidsai/cudf/pull/19980#issuecomment-3340039980
 python -m pytest --cache-clear "$@" "tests/experimental" \
     --executor streaming \
     --scheduler distributed \
+    --numprocesses=0 \
     --cov-fail-under=0  # No code-coverage requirement for these tests.
diff --git a/ci/test_python_other.sh b/ci/test_python_other.sh
index e69fbd52107..dcaa81a1e8b 100755
--- a/ci/test_python_other.sh
+++ b/ci/test_python_other.sh
@@ -43,7 +43,7 @@ rapids-logger "pytest custreamz"
 rapids-logger "pytest cudf-polars"
 ./ci/run_cudf_polars_pytests.sh \
   --junitxml="${RAPIDS_TESTS_DIR}/junit-cudf-polars.xml" \
-  --numprocesses=6 \
+  --numprocesses=8 \
   --dist=worksteal \
   --cov-config=./pyproject.toml \
   --cov=cudf_polars \
diff --git a/ci/test_wheel_cudf_polars.sh b/ci/test_wheel_cudf_polars.sh
index b2683eeadbc..07ed60e6835 100755
--- a/ci/test_wheel_cudf_polars.sh
+++ b/ci/test_wheel_cudf_polars.sh
@@ -71,6 +71,8 @@ for version in "${VERSIONS[@]}"; do
 
     ./ci/run_cudf_polars_pytests.sh \
         "${COVERAGE_ARGS[@]}" \
+        --numprocesses=8 \
+        --dist=worksteal \
         --junitxml="${RAPIDS_TESTS_DIR}/junit-cudf-polars-${version}.xml"
 
     if [ $? -ne 0 ]; then

From 161d226f9289ccb401be6b06b207a1438b3afda9 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Mon, 29 Sep 2025 10:07:30 -0700
Subject: [PATCH 2/4] Change to function scope

---
 python/cudf_polars/tests/experimental/conftest.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/python/cudf_polars/tests/experimental/conftest.py b/python/cudf_polars/tests/experimental/conftest.py
index c01c82a4a95..f1f439ce10d 100644
--- a/python/cudf_polars/tests/experimental/conftest.py
+++ b/python/cudf_polars/tests/experimental/conftest.py
@@ -7,7 +7,7 @@
 import pytest
 
 
-@pytest.fixture(autouse=True)
+@pytest.fixture(scope="session", autouse=True)
 def dask_cluster(pytestconfig, worker_id):
     if (
         pytestconfig.getoption("--scheduler") == "distributed"

From c2d6a05998687cf116c04e9b5d3358feed7b1979 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Mon, 29 Sep 2025 10:55:41 -0700
Subject: [PATCH 3/4] comment on session scoping

---
 python/cudf_polars/tests/experimental/conftest.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/python/cudf_polars/tests/experimental/conftest.py b/python/cudf_polars/tests/experimental/conftest.py
index f1f439ce10d..3d50e65a6c6 100644
--- a/python/cudf_polars/tests/experimental/conftest.py
+++ b/python/cudf_polars/tests/experimental/conftest.py
@@ -7,7 +7,9 @@
 import pytest
 
 
-@pytest.fixture(scope="session", autouse=True)
+# scope="session" is important to not cause singificant slowdowns in CI
+# https://github.com/rapidsai/cudf/pull/20137
+@pytest.fixture(autouse=True, scope="session")
 def dask_cluster(pytestconfig, worker_id):
     if (
         pytestconfig.getoption("--scheduler") == "distributed"

From f4554de361f598d3a58be6363df6ab8afdfe4ec2 Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Tue, 30 Sep 2025 10:24:44 -0700
Subject: [PATCH 4/4] Try removing 0 processes for distributed tests after
 session scoping fix

---
 ci/run_cudf_polars_pytests.sh | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/ci/run_cudf_polars_pytests.sh b/ci/run_cudf_polars_pytests.sh
index e7a9837cd66..304573d6a85 100755
--- a/ci/run_cudf_polars_pytests.sh
+++ b/ci/run_cudf_polars_pytests.sh
@@ -18,10 +18,7 @@ python -m pytest --cache-clear "$@" tests --executor streaming
 python -m pytest --cache-clear "$@" tests --executor streaming --blocksize-mode small
 
 # Run experimental tests with Distributed cluster
-# Runtime in CI tends to increase when running these tests with multiple processes.
-# https://github.com/rapidsai/cudf/pull/19980#issuecomment-3340039980
 python -m pytest --cache-clear "$@" "tests/experimental" \
     --executor streaming \
     --scheduler distributed \
-    --numprocesses=0 \
     --cov-fail-under=0  # No code-coverage requirement for these tests.