Add way to print JIT related info at shutdown

Added a runtime option called -XX:DumpJITInfoOnShutdown with prints
various interesting JIT statistics during the shutdown of the runtime
if enabled.

Example of running EvaluateAndApplyChanges with the option:
I art     : Code cache size=427KB data cache size=84KB num methods=1598
I art     : Start Dumping histograms for 1598 iterations for JIT timings
I art     : Compiling: Sum: 727.850ms 99% C.I. 135us-4402us Avg: 455.475us Max: 15567us
I art     : Verifying: Sum: 191.074ms 99% C.I. 19us-1450.500us Avg: 119.570us Max: 5142us
I art     : TrimMaps:  Sum: 62.053ms 99% C.I. 13us-199.374us Avg: 38.831us Max: 10058us
I art     : MakeExecutable:  Sum: 11.153ms 99% C.I. 4us-47us Avg: 6.979us Max: 47us
I art     : Initializing:  Sum: 7.991ms 99% C.I. 1us-49.781us Avg: 5us Max: 4852us
I art     : Done Dumping histograms

Bug: 17950037
Change-Id: I23538b24f947e5f6934f55579b8baa9d806eb3d5

3 files changed, 36 insertions, 2 deletions

diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 539c181..9b89459 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -40,16 +40,32 @@ JitOptions* JitOptions::CreateFromRuntimeArguments(const RuntimeArgumentMap& opt
       options.GetOrDefault(RuntimeArgumentMap::JITCodeCacheCapacity);
   jit_options->compile_threshold_ =
       options.GetOrDefault(RuntimeArgumentMap::JITCompileThreshold);
+  jit_options->dump_info_on_shutdown_ =
+      options.Exists(RuntimeArgumentMap::DumpJITInfoOnShutdown);
   return jit_options;
 }
 
+void Jit::DumpInfo(std::ostream& os) {
+  os << "Code cache size=" << PrettySize(code_cache_->CodeCacheSize())
+     << " data cache size=" << PrettySize(code_cache_->DataCacheSize())
+     << " num methods=" << code_cache_->NumMethods()
+     << "\n";
+  cumulative_timings_.Dump(os);
+}
+
+void Jit::AddTimingLogger(const TimingLogger& logger) {
+  cumulative_timings_.AddLogger(logger);
+}
+
 Jit::Jit()
     : jit_library_handle_(nullptr), jit_compiler_handle_(nullptr), jit_load_(nullptr),
-      jit_compile_method_(nullptr) {
+      jit_compile_method_(nullptr), dump_info_on_shutdown_(false),
+      cumulative_timings_("JIT timings") {
 }
 
 Jit* Jit::Create(JitOptions* options, std::string* error_msg) {
   std::unique_ptr<Jit> jit(new Jit);
+  jit->dump_info_on_shutdown_ = options->DumpJitInfoOnShutdown();
   if (!jit->LoadCompiler(error_msg)) {
     return nullptr;
   }
@@ -133,6 +149,9 @@ void Jit::DeleteThreadPool() {
 }
 
 Jit::~Jit() {
+  if (dump_info_on_shutdown_) {
+    DumpInfo(LOG(INFO));
+  }
   DeleteThreadPool();
   if (jit_compiler_handle_ != nullptr) {
     jit_unload_(jit_compiler_handle_);
diff --git a/runtime/jit/jit.h b/runtime/jit/jit.h
index b80015f..6b206d1 100644
--- a/runtime/jit/jit.h
+++ b/runtime/jit/jit.h
@@ -24,6 +24,7 @@
 #include "atomic.h"
 #include "base/macros.h"
 #include "base/mutex.h"
+#include "base/timing_logger.h"
 #include "gc_root.h"
 #include "jni.h"
 #include "object_callbacks.h"
@@ -61,6 +62,11 @@ class Jit {
     return code_cache_.get();
   }
   void DeleteThreadPool();
+  // Dump interesting info: #methods compiled, code vs data size, compile / verify cumulative
+  // loggers.
+  void DumpInfo(std::ostream& os);
+  // Add a timing logger to cumulative_timings_.
+  void AddTimingLogger(const TimingLogger& logger);
 
  private:
   Jit();
@@ -73,6 +79,10 @@ class Jit {
   void (*jit_unload_)(void*);
   bool (*jit_compile_method_)(void*, mirror::ArtMethod*, Thread*);
 
+  // Performance monitoring.
+  bool dump_info_on_shutdown_;
+  CumulativeLogger cumulative_timings_;
+
   std::unique_ptr<jit::JitInstrumentationCache> instrumentation_cache_;
   std::unique_ptr<jit::JitCodeCache> code_cache_;
   CompilerCallbacks* compiler_callbacks_;  // Owned by the jit compiler.
@@ -87,12 +97,16 @@ class JitOptions {
   size_t GetCodeCacheCapacity() const {
     return code_cache_capacity_;
   }
+  bool DumpJitInfoOnShutdown() const {
+    return dump_info_on_shutdown_;
+  }
 
  private:
   size_t code_cache_capacity_;
   size_t compile_threshold_;
+  bool dump_info_on_shutdown_;
 
-  JitOptions() : code_cache_capacity_(0), compile_threshold_(0) {
+  JitOptions() : code_cache_capacity_(0), compile_threshold_(0), dump_info_on_shutdown_(false) {
   }
 };
 
diff --git a/runtime/jit/jit_code_cache.cc b/runtime/jit/jit_code_cache.cc
index 4ae4d57..4d367e0 100644
--- a/runtime/jit/jit_code_cache.cc
+++ b/runtime/jit/jit_code_cache.cc
@@ -77,6 +77,7 @@ uint8_t* JitCodeCache::ReserveCode(Thread* self, size_t size) {
   if (size > CodeCacheRemain()) {
     return nullptr;
   }
+  ++num_methods_;  // TODO: This is hacky but works since each method has exactly one code region.
   code_cache_ptr_ += size;
   return code_cache_ptr_ - size;
 }