[Lldb-commits] [PATCH] D93657: [lldb] Ad os_signpost support to `lldb_private::Timer`

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere created this revision.
JDevlieghere added a reviewer: LLDB.
JDevlieghere requested review of this revision.

Emit `os_signposts` when supported from LLDB's timer class. A vast amount of performance sensitive places in LLDB are already instrumented with the Timer class. By emitting signposts we can  examine this information in Instruments. I recommend looking at Daniel's differential for why this is so powerful: https://reviews.llvm.org/D52954.


https://reviews.llvm.org/D93657

Files:
  lldb/include/lldb/Utility/Timer.h
  lldb/source/Utility/Timer.cpp


Index: lldb/source/Utility/Timer.cpp
===================================================================
--- lldb/source/Utility/Timer.cpp
+++ lldb/source/Utility/Timer.cpp
@@ -7,6 +7,8 @@
 //===----------------------------------------------------------------------===//
 #include "lldb/Utility/Timer.h"
 #include "lldb/Utility/Stream.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Signposts.h"
 
 #include <algorithm>
 #include <map>
@@ -28,6 +30,9 @@
 static std::atomic<Timer::Category *> g_categories;
 } // end of anonymous namespace
 
+/// Allows llvm::Timer to emit signposts when supported.
+static llvm::ManagedStatic<llvm::SignpostEmitter> Signposts;
+
 std::atomic<bool> Timer::g_quiet(true);
 std::atomic<unsigned> Timer::g_display_depth(0);
 static std::mutex &GetFileMutex() {
@@ -54,6 +59,7 @@
 
 Timer::Timer(Timer::Category &category, const char *format, ...)
     : m_category(category), m_total_start(std::chrono::steady_clock::now()) {
+  Signposts->startInterval(this, m_category.GetName());
   TimerStack &stack = GetTimerStackForCurrentThread();
 
   stack.push_back(this);
@@ -80,6 +86,8 @@
   auto total_dur = stop_time - m_total_start;
   auto timer_dur = total_dur - m_child_duration;
 
+  Signposts->endInterval(this, m_category.GetName());
+
   TimerStack &stack = GetTimerStackForCurrentThread();
   if (g_quiet && stack.size() <= g_display_depth) {
     std::lock_guard<std::mutex> lock(GetFileMutex());
Index: lldb/include/lldb/Utility/Timer.h
===================================================================
--- lldb/include/lldb/Utility/Timer.h
+++ lldb/include/lldb/Utility/Timer.h
@@ -25,6 +25,7 @@
   class Category {
   public:
     explicit Category(const char *category_name);
+    llvm::StringRef GetName() { return m_name; }
 
   private:
     friend class Timer;


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