From ba8132345cbae5b749b4a01deda732ad6f8251a0 Mon Sep 17 00:00:00 2001
From: Gangzheng Tong <tonggangzheng@gmail.com>
Date: Mon, 22 Sep 2025 15:46:42 -0700
Subject: Add RHI Device Caching and Test Prefix Exclusion (#8448)

# Add RHI Device Caching and Test Prefix Exclusion

## Summary

This PR introduces two key improvements to the Slang test
infrastructure:

1. **RHI Device Caching**: Implements device caching to significantly
speed up test execution by reusing graphics devices across tests, **RHI
Device Caching reduces slang-test execution time from ~15 minutes to ~5
minutes in Windows release builds**
2. **Test Prefix Exclusion**: Adds `-exclude-prefix` option to skip
tests matching specified path prefixes

## Changes

### RHI Device Caching
- **New `DeviceCache` class** (`slang-test-device-cache.h/cpp`):
Thread-safe device cache with LRU eviction (max 10 devices)
- **Cache control option**: `-cache-rhi-device` flag in both
`slang-test` and `render-test`
- Default: **enabled** in slang-test, **disabled** in render-test when
run standalone
  - Automatically skips caching for CUDA devices (due to driver issues)
- **Performance benefit**: Eliminates expensive device
creation/destruction cycles, especially beneficial for Vulkan on Tegra
platforms

### Test Prefix Exclusion
- **New `-exclude-prefix <prefix>` option** in slang-test
- Allows excluding entire test directories or patterns from execution
- Complements existing `-category` and individual test filtering options

### Usage Examples
```bash
# Enable device caching (default)
slang-test

# Disable device caching
slang-test -cache-rhi-device false

# Exclude tests from specific directories
slang-test -exclude-prefix tests/problematic/
slang-test -exclude-prefix tests/slow/ -exclude-prefix tests/experimental/
```

This change should significantly improve test execution performance,
particularly in CI environments with frequent device operations. This is
needed for running the GPU test in aarch64, where repeated device
creation/destroy is causing driver issues.

Needed by: https://github.com/shader-slang/slang/issues/8346

---------

Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>
Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>
---
 tools/slang-test/options.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

(limited to 'tools/slang-test/options.cpp')

diff --git a/tools/slang-test/options.cpp b/tools/slang-test/options.cpp
index ec30262fc..7a98caec6 100644
--- a/tools/slang-test/options.cpp
+++ b/tools/slang-test/options.cpp
@@ -76,6 +76,7 @@ static bool _isSubCommand(const char* arg)
         "  -verbose-paths                 Use verbose paths in output\n"
         "  -category <name>               Only run tests in specified category\n"
         "  -exclude <name>                Exclude tests in specified category\n"
+        "  -exclude-prefix <prefix>       Exclude tests with specified path prefix\n"
         "  -api <expr>                    Enable specific APIs (e.g., 'vk+dx12' or '+dx11')\n"
         "  -synthesizedTestApi <expr>     Set APIs for synthesized tests\n"
         "  -skip-api-detection            Skip API availability detection\n"
@@ -91,6 +92,7 @@ static bool _isSubCommand(const char* arg)
         "  -capability <name>             Compile with the given capability\n"
         "  -enable-debug-layers [true|false] Enable or disable Validation Layer for Vulkan\n"
         "                                 and Debug Device for DX\n"
+        "  -cache-rhi-device [true|false] Enable or disable RHI device caching (default: true)\n"
 #if _DEBUG
         "  -disable-debug-layers          Disable the debug layers (default enabled in debug "
         "build)\n"
@@ -357,6 +359,18 @@ static bool _isSubCommand(const char* arg)
                 optionsOut->excludeCategories.add(category, category);
             }
         }
+        else if (strcmp(arg, "-exclude-prefix") == 0)
+        {
+            if (argCursor == argEnd)
+            {
+                stdError.print("error: expected operand for '%s'\n", arg);
+                showHelp(stdError);
+                return SLANG_FAIL;
+            }
+            Slang::StringBuilder sb;
+            Slang::Path::simplify(*argCursor++, Slang::Path::SimplifyStyle::NoRoot, sb);
+            optionsOut->excludePrefixes.add(sb);
+        }
         else if (strcmp(arg, "-api") == 0)
         {
             if (argCursor == argEnd)
@@ -488,6 +502,26 @@ static bool _isSubCommand(const char* arg)
                 optionsOut->enableDebugLayers = false;
             }
         }
+        else if (strcmp(arg, "-cache-rhi-device") == 0)
+        {
+            optionsOut->cacheRhiDevice = true;
+
+            if (argCursor == argEnd)
+            {
+                stdError.print("error: expected operand for '%s'\n", arg);
+                showHelp(stdError);
+                return SLANG_FAIL;
+            }
+
+            // Check for false variants
+            const char* value = *argCursor++;
+            if (value[0] == 'f' || value[0] == 'F' || value[0] == 'n' || value[0] == 'N' ||
+                value[0] == '0' ||
+                ((value[0] == 'o' || value[0] == 'O') && (value[1] == 'f' || value[1] == 'F')))
+            {
+                optionsOut->cacheRhiDevice = false;
+            }
+        }
 #if _DEBUG
         else if (strcmp(arg, "-disable-debug-layers") == 0)
         {
-- 
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