testing/sched/rwsem_test: add comprehensive test suite for rwsem opti…

testing/sched/rwsem_test/CMakeLists.txt

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+# ##############################################################################
+# apps/testing/sched/rwsem_test/CMakeLists.txt
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License.  You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+# ##############################################################################
+
+if(CONFIG_TESTING_RWSEM_TEST)
+
+  nuttx_add_application(
+    NAME
+    rwsem_comprehensive_test
+    PRIORITY
+    ${CONFIG_TESTING_RWSEM_TEST_PRIORITY}
+    STACKSIZE
+    ${CONFIG_TESTING_RWSEM_TEST_STACKSIZE}
+    MODULE
+    ${CONFIG_TESTING_RWSEM_TEST}
+    SRCS
+    rwsem_comprehensive_test.c)
+
+endif()

testing/sched/rwsem_test/Kconfig

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+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config TESTING_RWSEM_TEST
+	tristate "Reader-Writer Semaphore Comprehensive Test"
+	default n
+	---help---
+		Enable reader-writer semaphore optimization test suite.
+		This test validates the rwsem optimization that reduces
+		unnecessary context switches.
+
+		Test Coverage:
+		- Core Correctness Tests (6 tests)
+		- Performance Tests (3 tests)
+		- Basic Functionality Tests (1 test)
+
+if TESTING_RWSEM_TEST
+
+config TESTING_RWSEM_TEST_PRIORITY
+	int "RWSem test task priority"
+	default 100
+
+config TESTING_RWSEM_TEST_STACKSIZE
+	int "RWSem test stack size"
+	default 8192
+
+endif

testing/sched/rwsem_test/Make.defs

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+############################################################################
+# apps/testing/sched/rwsem_test/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+ifneq ($(CONFIG_TESTING_RWSEM_TEST),)
+CONFIGURED_APPS += $(APPDIR)/testing/sched/rwsem_test
+endif

testing/sched/rwsem_test/Makefile

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+############################################################################
+# apps/testing/sched/rwsem_test/Makefile
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+include $(APPDIR)/Make.defs
+
+PRIORITY  = $(CONFIG_TESTING_RWSEM_TEST_PRIORITY)
+STACKSIZE = $(CONFIG_TESTING_RWSEM_TEST_STACKSIZE)
+MODULE    = $(CONFIG_TESTING_RWSEM_TEST)
+
+CFLAGS  += -I$(TOPDIR)/sched
+
+PROGNAME  = rwsem_comprehensive_test
+MAINSRC   = rwsem_comprehensive_test.c
+
+include $(APPDIR)/Application.mk

testing/sched/rwsem_test/README.md

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+# Reader-Writer Semaphore Test Suite
+
+## Overview
+
+This directory contains a comprehensive test suite for NuttX reader-writer semaphore (rwsem) optimization.
+
+**Commit ID**: `Id3b49dda0309b098f04e8ab499c28c94fe1f77ce`
+
+## Directory Structure
+
+```
+rwsem_test/
+├── CMakeLists.txt              # CMake build configuration
+├── Kconfig                     # Configuration options
+├── Make.defs                   # Make build system integration
+├── Makefile                    # Make build rules
+├── README.md                   # This file
+├── rwsem_comprehensive_test.c  # Test source code
+├── RWSEM_TEST_COVERAGE.md      # Test coverage details
+├── RWSEM_TEST_SUMMARY.md       # Test suite summary
+└── RWSEM_TEST_USAGE.md         # Usage instructions
+```
+
+## Quick Start
+
+### 1. Configuration
+
+```bash
+make menuconfig
+```
+
+Navigate to:
+```
+Application Configuration
+  └─> Testing
+      └─> Sched
+          └─> [*] Reader-Writer Semaphore Comprehensive Test
+```
+
+### 2. Build
+
+```bash
+make clean
+make
+```
+
+### 3. Run
+
+```bash
+nsh> rwsem_comprehensive_test
+```
+
+## Test Contents
+
+This test suite contains 10 comprehensive tests:
+
+### Core Correctness Tests (Community Required)
+1. Multiple readers with no writers
+2. Multiple writers (exclusive access)
+3. Mixed reader-writer access patterns
+4. Waiter wake-up correctness
+5. Lock holder tracking
+6. Context switch reduction verification
+
+### Performance Tests
+7. Recursive write lock performance
+8. Converted lock performance
+10. High contention multi-threaded performance
+
+### Basic Functionality Tests
+9. Basic operations
+
+## Optimization Description
+
+This optimization reduces unnecessary context switches by only calling `up_wait()` when the lock is actually available:
+
+- **up_write() optimization**: Only call `up_wait()` when `writer` reaches 0
+- **up_read() optimization**: Only call `up_read()` when `reader` reaches 0
+
+## Documentation
+
+- **RWSEM_TEST_USAGE.md** - Detailed usage instructions and troubleshooting
+- **RWSEM_TEST_COVERAGE.md** - Complete test coverage matrix
+- **RWSEM_TEST_SUMMARY.md** - Test suite summary and technical analysis
+
+## Configuration Options
+
+Configurable in `make menuconfig`:
+
+- `CONFIG_TESTING_RWSEM_TEST` - Enable/disable rwsem test
+- `CONFIG_TESTING_RWSEM_TEST_PRIORITY` - Test task priority (default 100)
+- `CONFIG_TESTING_RWSEM_TEST_STACKSIZE` - Test stack size (default 8192)
+
+## Expected Results
+
+All tests should pass with output similar to:
+
+```
+========================================
+RWSem Comprehensive Test Suite
+========================================
+...
+========================================
+ALL TESTS PASSED
+========================================
+```
+
+## Performance Metrics
+
+Tests report the following metrics:
+
+- Execution time
+- Average time per operation
+- Throughput (ops/ms)
+
+## Production Validation
+
+This optimization has been validated in production on **Vela OS** (Xiaomi's NuttX-based embedded OS) for months, running on:
+
+- Wearable devices
+- IoT devices
+- Automotive systems
+
+## Related Links
+
+- GitHub PR: https://github.com/apache/nuttx/pull/18210
+- Commit: Id3b49dda0309b098f04e8ab499c28c94fe1f77ce
+
+## Contact
+
+For questions, please ask in GitHub PR #18210.