Alternate half of linux arm64 CI runners from a100 to l4 (#864)

Change every other arm64 entry in the pull-request test matrix to use l4
GPU instead of a100, giving a ~50/50 split in an alternating pattern (8
a100, 7 l4 active; plus 2 commented-out 3.14t entries updated to match).
This reduces pressure on a100 runners while maintaining arm64 coverage
across all Python and CUDA version combinations.

Companion to NVIDIA/cuda-python#1956.

### Changes

- 7 of 15 active linux arm64 entries changed from `a100` to `l4` (every
even-numbered row)
- 2 of 3 commented-out 3.14t arm64 entries also updated (continuing the
alternation)
- Updated copyright year (2025 → 2026) and header comment to reflect
mixed GPU usage

### Resulting arm64 matrix

| # | PY_VER | CUDA_VER | GPU | Active? |
|---|--------|----------|-----|---------|
| 1 | 3.10 | 12.9.1 | a100 | yes |
| 2 | 3.10 | 13.0.2 | **l4** | yes |
| 3 | 3.10 | 13.2.1 | a100 | yes |
| 4 | 3.11 | 12.9.1 | **l4** | yes |
| 5 | 3.11 | 13.0.2 | a100 | yes |
| 6 | 3.11 | 13.2.1 | **l4** | yes |
| 7 | 3.12 | 12.9.1 | a100 | yes |
| 8 | 3.12 | 13.0.2 | **l4** | yes |
| 9 | 3.12 | 13.2.1 | a100 | yes |
| 10 | 3.13 | 12.9.1 | **l4** | yes |
| 11 | 3.13 | 13.0.2 | a100 | yes |
| 12 | 3.13 | 13.2.1 | **l4** | yes |
| 13 | 3.14 | 12.9.1 | a100 | yes |
| 14 | 3.14 | 13.0.2 | **l4** | yes |
| 15 | 3.14 | 13.2.1 | a100 | yes |
| 16 | 3.14t | 12.9.1 | **l4** | commented |
| 17 | 3.14t | 13.0.2 | a100 | commented |
| 18 | 3.14t | 13.2.1 | **l4** | commented |

-- Leo's bot

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: leofang

ci/test-matrix.yml

@@ -1,10 +1,10 @@
-# SPDX-FileCopyrightText: Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: BSD-2-Clause
 #
 # Test matrix configurations for CUDA Python CI workflows. This file consolidates
 # the test matrices that were previously hardcoded in the workflow files. All GPU
-# and ARCH values are hard-coded for each architecture: l4 GPU for amd64, a100 GPU
-# for arm64.
+# and ARCH values are hard-coded for each architecture: various GPUs for amd64,
+# alternating a100/l4 for arm64.
 #
 # Please keep the matrices sorted in ascending order by the following:
 #
@@ -39,23 +39,23 @@ linux:
     # - { ARCH: 'amd64', PY_VER: '3.14t', CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     # linux-aarch64
     - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '13.2.1', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.11',  CUDA_VER: '12.9.1', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.11',  CUDA_VER: '12.9.1', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.11',  CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.11',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.11',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.12',  CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.12',  CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.12',  CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.12',  CUDA_VER: '13.2.1', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.13',  CUDA_VER: '12.9.1', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.13',  CUDA_VER: '12.9.1', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.13',  CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.13',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.13',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.14',  CUDA_VER: '12.9.1', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    - { ARCH: 'arm64', PY_VER: '3.14',  CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'arm64', PY_VER: '3.14',  CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.14',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    # - { ARCH: 'arm64', PY_VER: '3.14t', CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    # - { ARCH: 'arm64', PY_VER: '3.14t', CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     # - { ARCH: 'arm64', PY_VER: '3.14t', CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
-    # - { ARCH: 'arm64', PY_VER: '3.14t', CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
+    # - { ARCH: 'arm64', PY_VER: '3.14t', CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     # special runners
     - { ARCH: 'amd64', PY_VER: '3.13',  CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'h100',       GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'amd64', PY_VER: '3.13',  CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'h100',       GPU_COUNT: '1', DRIVER: 'latest' }