Add unit tests

sycl/include/sycl/detail/os_util.hpp

@@ -99,6 +99,8 @@ class __SYCL_EXPORT OSUtil {
   // Get list of all files in the directory along with its last access time.
   static std::vector<std::pair<time_t, std::string>>
   getFilesWithAccessTime(const std::string &Path);
+
+  static size_t DirSizeVar;
 };
 
 } // namespace detail

sycl/source/detail/os_util.cpp

@@ -26,6 +26,7 @@
 #include <cstring>
 #include <dlfcn.h>
 #include <fstream>
+#include <ftw.h>    // for ftw - file tree walk
 #include <libgen.h> // for dirname
 #include <link.h>
 #include <linux/limits.h> // for PATH_MAX
@@ -276,22 +277,25 @@ int OSUtil::makeDir(const char *Dir) {
   return 0;
 }
 
+size_t OSUtil::DirSizeVar = 0;
 // Get size of a directory in bytes.
 size_t OSUtil::getDirectorySize(const std::string &Path) {
 
-  size_t Size = 0;
-#if __GNUC__ && __GNUC__ < 8
-  // Should we worry about this case?
-  assert(false && "getDirectorySize is not implemented for GCC < 8");
-#else
-  // Use C++17 filesystem API to get the size of the directory.
-  for (const auto &entry :
-       std::filesystem::recursive_directory_iterator(Path)) {
-    if (entry.is_regular_file())
-      Size += entry.file_size();
-  }
+  DirSizeVar = 0;
+// Use ftw for Linux and darwin as they support posix.
+#if defined(__SYCL_RT_OS_LINUX) || defined(__SYCL_RT_OS_DARWIN)
+  auto SumSize =
+          [](const char *Fpath, const struct stat *StatBuf, int TypeFlag) {
+            if (TypeFlag == FTW_F)
+              DirSizeVar += StatBuf->st_size;
+            return 0;
+          };
+
+  if (ftw(Path.c_str(),SumSize, 1) == -1)
+    std::cerr << "Failed to get directory size: " << Path << std::endl;
 #endif
-  return Size;
+
+  return DirSizeVar;
 }
 
 // Get size of file in bytes.

sycl/source/detail/persistent_device_code_cache.cpp

@@ -182,6 +182,11 @@ getProgramBinaryData(const ur_program_handle_t &NativePrg,
 // If not, create it and populate it with the size of the cache directory.
 void PersistentDeviceCodeCache::repopulateCacheSizeFile(
     const std::string &CacheRoot) {
+
+  // No need to store cache size if eviction is disabled.
+  if (!isEvictionEnabled())
+    return;
+
   const std::string CacheSizeFileName = "cache_size.txt";
   const std::string CacheSizeFile = CacheRoot + "/" + CacheSizeFileName;
 
@@ -193,8 +198,6 @@ void PersistentDeviceCodeCache::repopulateCacheSizeFile(
     // Calculate the size of the cache directory.
     size_t CacheSize = OSUtil::getDirectorySize(CacheRoot);
 
-    std::cerr << "Cache size: " << CacheSize << std::endl;
-
     // Take the lock to write the cache size to the file.
     {
       LockCacheItem Lock{CacheSizeFile};
@@ -311,6 +314,10 @@ void PersistentDeviceCodeCache::evictItemsFromCache(
 void PersistentDeviceCodeCache::updateCacheFileSizeAndTriggerEviction(
     const std::string &CacheRoot, size_t ItemSize) {
 
+  // No need to store cache size if eviction is disabled.
+  if (!isEvictionEnabled())
+    return;
+
   const std::string CacheSizeFileName = "cache_size.txt";
   const std::string CacheSizeFile = CacheRoot + "/" + CacheSizeFileName;
   size_t CurrentCacheSize = 0;
@@ -336,7 +343,6 @@ void PersistentDeviceCodeCache::updateCacheFileSizeAndTriggerEviction(
 
       // Write the updated cache size to the file.
       FileStream.open(CacheSizeFile, std::ios::out | std::ios::trunc);
-      std::cerr << "Current cache size: " << CurrentCacheSize << std::endl;
       FileStream << CurrentCacheSize;
       FileStream.close();
       break;
@@ -345,9 +351,6 @@ void PersistentDeviceCodeCache::updateCacheFileSizeAndTriggerEviction(
 
   // Check if the cache size exceeds the threshold and trigger cache eviction if
   // needed.
-  if (!SYCLConfig<SYCL_CACHE_MAX_SIZE>::isPersistentCacheEvictionEnabled())
-    return;
-
   size_t MaxCacheSize = SYCLConfig<SYCL_CACHE_MAX_SIZE>::getProgramCacheSize();
   if (CurrentCacheSize > MaxCacheSize) {
     // Trigger cache eviction.

sycl/source/detail/persistent_device_code_cache.hpp

@@ -118,9 +118,6 @@ class PersistentDeviceCodeCache {
       const std::vector<const RTDeviceBinaryImage *> &SortedImgs,
       const SerializedObj &SpecConsts, const std::string &BuildOptionsString);
 
-  /* Returns the path to directory storing persistent device code cache.*/
-  static std::string getRootDir();
-
   /* Form string representing device version */
   static std::string getDeviceIDString(const device &Device);
 
@@ -152,6 +149,9 @@ class PersistentDeviceCodeCache {
       1024 * 1024 * 1024;
 
 public:
+  /* Returns the path to directory storing persistent device code cache.*/
+  static std::string getRootDir();
+
   /* Check if on-disk cache enabled.
    */
   static bool isEnabled();
@@ -228,6 +228,11 @@ class PersistentDeviceCodeCache {
   // Evict LRU items from the cache to make space for new items.
   static void evictItemsFromCache(const std::string &CacheRoot,
                                   size_t CacheSize, size_t MaxCacheSize);
+
+  // Check if eviction is enabled.
+  static bool isEvictionEnabled() {
+    return SYCLConfig<SYCL_CACHE_MAX_SIZE>::isPersistentCacheEvictionEnabled();
+  }
 };
 } // namespace detail
 } // namespace _V1

sycl/unittests/kernel-and-program/PersistentDeviceCodeCache.cpp

@@ -135,6 +135,12 @@ class PersistentDeviceCodeCache
     SYCLCachePersistentChanged = true;
   }
 
+  // Set SYCL_CACHE_MAX_SIZE.
+  void SetDiskCacheEvictionEnv(const char *NewValue) {
+    set_env("SYCL_CACHE_MAX_SIZE", NewValue);
+    sycl::detail::SYCLConfig<sycl::detail::SYCL_CACHE_MAX_SIZE>::reset();
+  }
+
   void AppendToSYCLCacheDirEnv(const char *SubDir) {
     std::string NewSYCLCacheDirPath{RootSYCLCacheDir};
     if (NewSYCLCacheDirPath.back() != '\\' && NewSYCLCacheDirPath.back() != '/')
@@ -144,6 +150,24 @@ class PersistentDeviceCodeCache
     sycl::detail::SYCLConfig<sycl::detail::SYCL_CACHE_DIR>::reset();
   }
 
+  // Get the list of binary files in the cache directory.
+  std::vector<std::string> getBinaryFileNames(std::string CachePath) {
+
+    std::vector<std::string> FileNames;
+    std::error_code EC;
+    for (llvm::sys::fs::directory_iterator DirIt(CachePath, EC);
+         DirIt != llvm::sys::fs::directory_iterator(); DirIt.increment(EC)) {
+      // Check if the file is a binary file.
+      std::string filename = DirIt->path();
+      if (filename.find(".bin") != std::string::npos) {
+        // Just return the file name without the path.
+        FileNames.push_back(filename.substr(filename.find_last_of("/\\") + 1));
+      }
+    }
+
+    return FileNames;
+  }
+
   void ResetSYCLCacheDirEnv() {
     set_env("SYCL_CACHE_DIR", RootSYCLCacheDir.c_str());
     sycl::detail::SYCLConfig<sycl::detail::SYCL_CACHE_DIR>::reset();
@@ -169,6 +193,9 @@ class PersistentDeviceCodeCache
       SetSYCLCachePersistentEnv(SYCLCachePersistentBefore
                                     ? SYCLCachePersistentBefore->c_str()
                                     : nullptr);
+
+    // Reset SYCL_CACHE_MAX_SIZE.
+    SetDiskCacheEvictionEnv(nullptr);
     ResetSYCLCacheDirEnv();
   }
 
@@ -519,6 +546,99 @@ TEST_P(PersistentDeviceCodeCache, AccessDeniedForCacheDir) {
 }
 #endif //_WIN32
 
+// Unit tests for testing eviction in persistent cache.
+TEST_P(PersistentDeviceCodeCache, BasicEviction) {
+
+  // Cleanup the cache directory.
+  std::string CacheRoot = detail::PersistentDeviceCodeCache::getRootDir();
+  ASSERT_NO_ERROR(llvm::sys::fs::remove_directories(CacheRoot));
+  ASSERT_NO_ERROR(llvm::sys::fs::create_directories(CacheRoot));
+
+  // Disable eviction for the time being.
+  SetDiskCacheEvictionEnv("0");
+
+  std::string BuildOptions{"--eviction"};
+  // Put 3 items to the cache.
+  // Sleeping for 1 second between each put to ensure that the items are
+  // written to the cache with different timestamps. After that, we will
+  // have three binary files in the cache with different timestamps. This is
+  // required to keep this unit test deterministic.
+  detail::PersistentDeviceCodeCache::putItemToDisc({Dev}, {&Img}, {},
+                                                   BuildOptions, NativeProg);
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+
+  detail::PersistentDeviceCodeCache::putItemToDisc({Dev}, {&Img}, {},
+                                                   BuildOptions, NativeProg);
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+
+  detail::PersistentDeviceCodeCache::putItemToDisc({Dev}, {&Img}, {},
+                                                   BuildOptions, NativeProg);
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+
+  // Retrieve 0.bin from the cache.
+  auto Res = detail::PersistentDeviceCodeCache::getItemFromDisc(
+      {Dev}, {&Img}, {}, BuildOptions);
+
+  // Get the number of binary files in the cached item folder.
+  std::string ItemDir = detail::PersistentDeviceCodeCache::getCacheItemPath(
+      Dev, {&Img}, {}, BuildOptions);
+  auto BinFiles = getBinaryFileNames(ItemDir);
+
+  EXPECT_EQ(BinFiles.size(), static_cast<size_t>(3))
+      << "Missing binary files. Eviction should not have happened.";
+
+  // Get Cache size and size of each entry. Set eviction threshold so that
+  // just one item is evicted.
+  size_t CurrentCacheSize = 0;
+  size_t SizeOfOneEntry =
+      (size_t)(detail::OSUtil::getDirectorySize(CacheRoot)) + 10;
+
+  // Set SYCL_CACHE_MAX_SIZE.
+  SetDiskCacheEvictionEnv(std::to_string(SizeOfOneEntry).c_str());
+
+  // Put 4th item to the cache. This should trigger eviction. Only the first
+  // item should be evicted.
+  detail::PersistentDeviceCodeCache::putItemToDisc({Dev}, {&Img}, {},
+                                                   BuildOptions, NativeProg);
+
+  // We should have three binary files: 0.bin, 2.bin, 3.bin.
+  BinFiles = getBinaryFileNames(ItemDir);
+  EXPECT_EQ(BinFiles.size(), static_cast<size_t>(3))
+      << "Eviction failed. Wrong number of binary files in the cache.";
+
+  // Check that 1.bin was evicted.
+  for (const auto &File : BinFiles) {
+    EXPECT_NE(File, "1.bin")
+        << "Eviction failed. 1.bin should have been evicted.";
+  }
+
+  ASSERT_NO_ERROR(llvm::sys::fs::remove_directories(ItemDir));
+}
+
+// Unit test for testing size file creation and update, concurrently.
+TEST_P(PersistentDeviceCodeCache, ConcurentReadWriteCacheFileSize) {
+  // Cleanup the cache directory.
+  std::string CacheRoot = detail::PersistentDeviceCodeCache::getRootDir();
+  ASSERT_NO_ERROR(llvm::sys::fs::remove_directories(CacheRoot));
+  ASSERT_NO_ERROR(llvm::sys::fs::create_directories(CacheRoot));
+
+  // Insanely large value to not trigger eviction. This test just checks
+  // for deadlocks/crashes when updating the size file concurrently.
+  SetDiskCacheEvictionEnv("10000000");
+  ConcurentReadWriteCache(1, 50);
+}
+
+// Unit test for adding and evicting cache, concurrently.
+TEST_P(PersistentDeviceCodeCache, ConcurentReadWriteCacheEviction) {
+  // Cleanup the cache directory.
+  std::string CacheRoot = detail::PersistentDeviceCodeCache::getRootDir();
+  ASSERT_NO_ERROR(llvm::sys::fs::remove_directories(CacheRoot));
+  ASSERT_NO_ERROR(llvm::sys::fs::create_directories(CacheRoot));
+
+  SetDiskCacheEvictionEnv("1000");
+  ConcurentReadWriteCache(2, 40);
+}
+
 INSTANTIATE_TEST_SUITE_P(PersistentDeviceCodeCacheImpl,
                          PersistentDeviceCodeCache,
                          ::testing::Values(SYCL_DEVICE_BINARY_TYPE_SPIRV,