add thread-local cache for string handle lookups

Author: eparshut

cpp/include/ittapi_domain.hpp

@@ -93,26 +93,26 @@ class Domain
 
     void task_begin(std::string_view name) const
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_handle, detail::make_null_id(), detail::make_null_id(), h);
     }
 
     void task_begin(std::string_view name, __itt_id taskid, __itt_id parentid) const
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_handle, taskid, parentid, h);
     }
 
 #if ITT_PLATFORM == ITT_PLATFORM_WIN
     void task_begin(std::wstring_view name) const
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_handle, detail::make_null_id(), detail::make_null_id(), h);
     }
 
     void task_begin(std::wstring_view name, __itt_id taskid, __itt_id parentid) const
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_handle, taskid, parentid, h);
     }
 #endif

cpp/include/ittapi_region.hpp

@@ -25,7 +25,7 @@ class ScopedRegion
         , m_id(detail::make_null_id())
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_region_begin(m_domain, m_id, detail::make_null_id(), h);
     }
 
@@ -35,7 +35,7 @@ class ScopedRegion
         , m_id(id)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_region_begin(m_domain, m_id, parentid, h);
     }
 
@@ -45,7 +45,7 @@ class ScopedRegion
         , m_id(detail::make_null_id())
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_region_begin(m_domain, m_id, detail::make_null_id(), h);
     }
 
@@ -55,7 +55,7 @@ class ScopedRegion
         , m_id(id)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_region_begin(m_domain, m_id, parentid, h);
     }
 #endif

cpp/include/ittapi_task.hpp

@@ -24,7 +24,7 @@ class ScopedTask
         : m_domain(domain)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_domain, detail::make_null_id(), detail::make_null_id(), h);
     }
 
@@ -33,7 +33,7 @@ class ScopedTask
         : m_domain(domain)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::string(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_domain, taskid, parentid, h);
     }
 
@@ -42,7 +42,7 @@ class ScopedTask
         : m_domain(domain)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_domain, detail::make_null_id(), detail::make_null_id(), h);
     }
 
@@ -51,7 +51,7 @@ class ScopedTask
         : m_domain(domain)
         , m_active(true)
     {
-        __itt_string_handle* h = detail::create_string_handle(std::wstring(name).c_str());
+        __itt_string_handle* h = detail::get_or_create_string_handle(name);
         __itt_task_begin(m_domain, taskid, parentid, h);
     }
 #endif

cpp/include/ittapi_utils.hpp

@@ -8,6 +8,9 @@
 
 #include <ittnotify.h>
 
+#include <string_view>
+#include <unordered_map>
+
 namespace ittapi
 {
 namespace detail
@@ -31,6 +34,22 @@ inline __itt_string_handle* create_string_handle(const char* name) noexcept
 #endif
 }
 
+inline __itt_string_handle* get_or_create_string_handle(std::string_view name)
+{
+    thread_local std::unordered_map<std::string_view, __itt_string_handle*> cache;
+    auto it = cache.find(name);
+    if (it != cache.end())
+    {
+        return it->second;
+    }
+    __itt_string_handle* h = create_string_handle(std::string(name).c_str());
+    if (h != nullptr)
+    {
+        cache.emplace(h->strA, h);
+    }
+    return h;
+}
+
 inline void thread_set_name(const char* name) noexcept
 {
 #if ITT_PLATFORM == ITT_PLATFORM_WIN
@@ -52,6 +71,22 @@ inline __itt_string_handle* create_string_handle(const wchar_t* name) noexcept
     return __itt_string_handle_createW(name);
 }
 
+inline __itt_string_handle* get_or_create_string_handle(std::wstring_view name)
+{
+    thread_local std::unordered_map<std::wstring_view, __itt_string_handle*> cache;
+    auto it = cache.find(name);
+    if (it != cache.end())
+    {
+        return it->second;
+    }
+    __itt_string_handle* h = create_string_handle(std::wstring(name).c_str());
+    if (h != nullptr)
+    {
+        cache.emplace(h->strW, h);
+    }
+    return h;
+}
+
 inline void thread_set_name(const wchar_t* name) noexcept
 {
     __itt_thread_set_nameW(name);