From 7c2c456eeeffa18b3d1b0b1692e6305b47ffb24f Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Wed, 8 Oct 2014 14:56:46 -0700
Subject: [PATCH] Bug 1079657 - DMD: Remove the "stress" mode. r=erahm.

--HG--
extra : rebase_source : d0b233a62c1b50facb27d781f9942628f100180e
---
 memory/replace/dmd/DMD.cpp | 95 +-------------------------------------
 1 file changed, 2 insertions(+), 93 deletions(-)

diff --git a/memory/replace/dmd/DMD.cpp b/memory/replace/dmd/DMD.cpp
index b0ec4f1287da..d889cf463efc 100644
--- a/memory/replace/dmd/DMD.cpp
+++ b/memory/replace/dmd/DMD.cpp
@@ -291,8 +291,7 @@ class Options
 
   enum Mode {
     Normal,   // run normally
-    Test,     // do some basic correctness tests
-    Stress    // do some performance stress tests
+    Test      // do some basic correctness tests
   };
 
   char* mDMDEnvVar;   // a saved copy, for later printing
@@ -320,7 +319,6 @@ public:
   void SetSampleBelowSize(size_t aN) { mSampleBelowSize.mActual = aN; }
 
   bool IsTestMode()   const { return mMode == Test; }
-  bool IsStressMode() const { return mMode == Stress; }
 };
 
 static Options *gOptions;
@@ -1320,8 +1318,6 @@ Options::Options(const char* aDMDEnvVar)
         mMode = Options::Normal;
       } else if (strcmp(arg, "--mode=test")   == 0) {
         mMode = Options::Test;
-      } else if (strcmp(arg, "--mode=stress") == 0) {
-        mMode = Options::Stress;
 
       } else if (strcmp(arg, "") == 0) {
         // This can only happen if there is trailing whitespace.  Ignore.
@@ -1358,7 +1354,7 @@ Options::BadArg(const char* aArg)
             int(mMaxFrames.mMax),
             int(mMaxFrames.mDefault));
   StatusMsg("  --show-dump-stats=<yes|no>   Show stats about dumps? [no]\n");
-  StatusMsg("  --mode=<normal|test|stress>  Mode of operation [normal]\n");
+  StatusMsg("  --mode=<normal|test>         Mode of operation [normal]\n");
   StatusMsg("\n");
   exit(1);
 }
@@ -1389,7 +1385,6 @@ OpenOutputFile(const char* aFilename)
 
 static void RunTestMode(UniquePtr<FpWriteFunc> aF1, UniquePtr<FpWriteFunc> aF2,
                         UniquePtr<FpWriteFunc> aF3, UniquePtr<FpWriteFunc> aF4);
-static void RunStressMode(UniquePtr<FpWriteFunc> aF);
 
 // WARNING: this function runs *very* early -- before all static initializers
 // have run.  For this reason, non-scalar globals such as gStateLock and
@@ -1462,16 +1457,6 @@ Init(const malloc_table_t* aMallocTable)
     exit(0);
   }
 
-  if (gOptions->IsStressMode()) {
-    auto f = MakeUnique<FpWriteFunc>(OpenOutputFile("stress.json"));
-    gIsDMDRunning = true;
-
-    StatusMsg("running stress mode...\n");
-    RunStressMode(Move(f));
-    StatusMsg("finished stress mode\n");
-    exit(0);
-  }
-
   gIsDMDRunning = true;
 }
 
@@ -2088,81 +2073,5 @@ RunTestMode(UniquePtr<FpWriteFunc> aF1, UniquePtr<FpWriteFunc> aF2,
   AnalyzeReports(writer4);
 }
 
-//---------------------------------------------------------------------------
-// Stress testing microbenchmark
-//---------------------------------------------------------------------------
-
-// This stops otherwise-unused variables from being optimized away.
-static void
-UseItOrLoseIt2(void* a)
-{
-  if (a == (void*)0x42) {
-    printf("UseItOrLoseIt2\n");
-  }
-}
-
-MOZ_NEVER_INLINE static void
-stress5()
-{
-  for (int i = 0; i < 10; i++) {
-    void* x = malloc(64);
-    UseItOrLoseIt2(x);
-    if (i & 1) {
-      free(x);
-    }
-  }
-}
-
-MOZ_NEVER_INLINE static void
-stress4()
-{
-  stress5(); stress5(); stress5(); stress5(); stress5();
-  stress5(); stress5(); stress5(); stress5(); stress5();
-}
-
-MOZ_NEVER_INLINE static void
-stress3()
-{
-  for (int i = 0; i < 10; i++) {
-    stress4();
-  }
-}
-
-MOZ_NEVER_INLINE static void
-stress2()
-{
-  stress3(); stress3(); stress3(); stress3(); stress3();
-  stress3(); stress3(); stress3(); stress3(); stress3();
-}
-
-MOZ_NEVER_INLINE static void
-stress1()
-{
-  for (int i = 0; i < 10; i++) {
-    stress2();
-  }
-}
-
-// This stress test does lots of allocations and frees, which is where most of
-// DMD's overhead occurs.  It allocates 1,000,000 64-byte blocks, spread evenly
-// across 1,000 distinct stack traces.  It frees every second one immediately
-// after allocating it.
-//
-// It's highly artificial, but it's deterministic and easy to run.  It can be
-// timed under different conditions to glean performance data.
-static void
-RunStressMode(UniquePtr<FpWriteFunc> aF)
-{
-  JSONWriter writer(Move(aF));
-
-  // Disable sampling for maximum stress.
-  gOptions->SetSampleBelowSize(1);
-
-  stress1(); stress1(); stress1(); stress1(); stress1();
-  stress1(); stress1(); stress1(); stress1(); stress1();
-
-  AnalyzeReports(writer);
-}
-
 }   // namespace dmd
 }   // namespace mozilla