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/*
* Copyright (C) 2012 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include <wtf/StackStats.h>
#if ENABLE(STACK_STATS)
#include <wtf/Assertions.h>
#include <wtf/DataLog.h>
// Define the following flag if you want to collect stats on every single
// checkpoint. By default, we only log checkpoints that establish new
// max values.
#define ENABLE_VERBOSE_STACK_STATS 1
namespace WTF {
// CheckPoint management:
Lock StackStats::s_sharedMutex;
StackStats::CheckPoint* StackStats::s_topCheckPoint = 0;
StackStats::LayoutCheckPoint* StackStats::s_firstLayoutCheckPoint = 0;
StackStats::LayoutCheckPoint* StackStats::s_topLayoutCheckPoint = 0;
// High watermark stats:
int StackStats::s_maxCheckPointDiff = 0;
int StackStats::s_maxStackHeight = 0;
int StackStats::s_maxReentryDepth = 0;
int StackStats::s_maxLayoutCheckPointDiff = 0;
int StackStats::s_maxTotalLayoutCheckPointDiff = 0;
int StackStats::s_maxLayoutReentryDepth = 0;
StackStats::PerThreadStats::PerThreadStats()
{
const StackBounds& stack = Thread::current().stack();
m_reentryDepth = 0;
m_stackStart = (char*)stack.origin();
m_currentCheckPoint = 0;
dataLogF(" === THREAD new stackStart %p ========\n", m_stackStart);
}
StackStats::CheckPoint::CheckPoint()
{
std::lock_guard<Lock> lock(StackStats::s_sharedMutex);
Thread& thread = Thread::current();
StackStats::PerThreadStats& t = thread.stackStats();
const StackBounds& stack = thread.stack();
bool isGrowingDownward = stack.isGrowingDownward();
bool needToLog = false;
char* current = reinterpret_cast<char*>(this);
char* last = reinterpret_cast<char*>(t.m_currentCheckPoint);
// If there was no previous checkpoint, measure from the start of the stack:
if (!last)
last = t.m_stackStart;
// Update the reentry depth stats:
t.m_reentryDepth++;
if (t.m_reentryDepth > StackStats::s_maxReentryDepth) {
StackStats::s_maxReentryDepth = t.m_reentryDepth;
needToLog = true;
}
// Update the stack height stats:
int height = t.m_stackStart - current;
if (!isGrowingDownward)
height = -height;
if (height > StackStats::s_maxStackHeight) {
StackStats::s_maxStackHeight = height;
needToLog = true;
}
// Update the checkpoint diff stats:
int diff = last - current;
if (!isGrowingDownward)
diff = -diff;
if (diff > StackStats::s_maxCheckPointDiff) {
StackStats::s_maxCheckPointDiff = diff;
needToLog = true;
}
// Push this checkpoint:
m_prev = t.m_currentCheckPoint;
t.m_currentCheckPoint = this;
#if ENABLE(VERBOSE_STACK_STATS)
needToLog = true; // always log.
#endif
// Log this checkpoint if needed:
if (needToLog)
dataLogF(" CHECKPOINT %p diff %d/%.1fk/max %.1fk | reentry %d/max %d | height %.1fk/max %.1fk | stack %p size %.1fk\n",
this, diff, diff / 1024.0, StackStats::s_maxCheckPointDiff / 1024.0,
t.m_reentryDepth, StackStats::s_maxReentryDepth,
height / 1024.0, StackStats::s_maxStackHeight / 1024.0,
stack.origin(), stack.size() / 1024.0);
}
StackStats::CheckPoint::~CheckPoint()
{
std::lock_guard<Lock> lock(StackStats::s_sharedMutex);
Thread& thread = Thread::current();
StackStats::PerThreadStats& t = thread.stackStats();
// Pop to previous checkpoint:
t.m_currentCheckPoint = m_prev;
--t.m_reentryDepth;
// Log this checkpoint if needed:
#if ENABLE(VERBOSE_STACK_STATS)
if (!m_prev) {
const StackBounds& stack = thread.stack();
bool isGrowingDownward = stack.isGrowingDownward();
char* current = reinterpret_cast<char*>(this);
int height = t.m_stackStart - current;
if (!isGrowingDownward)
height = -height;
dataLogF(" POP to %p diff max %.1fk | reentry %d/%d max | height %.1fk/max %.1fk | stack %p size %.1fk)\n",
this, StackStats::s_maxCheckPointDiff / 1024.0,
t.m_reentryDepth, StackStats::s_maxReentryDepth,
height / 1024.0, StackStats::s_maxStackHeight / 1024.0,
stack.origin(), stack.size() / 1024.0);
}
#endif
}
void StackStats::probe()
{
std::lock_guard<Lock> lock(StackStats::s_sharedMutex);
Thread& thread = Thread::current();
StackStats::PerThreadStats& t = thread.stackStats();
const StackBounds& stack = thread.stack();
bool isGrowingDownward = stack.isGrowingDownward();
bool needToLog = false;
int dummy;
char* current = reinterpret_cast<char*>(&dummy);
char* last = reinterpret_cast<char*>(t.m_currentCheckPoint);
// If there was no previous checkpoint, measure from the start of the stack:
if (!last)
last = t.m_stackStart;
// We did not reach another checkpoint yet. Hence, we do not touch the
// reentry stats.
// Update the stack height stats:
int height = t.m_stackStart - current;
if (!isGrowingDownward)
height = -height;
if (height > StackStats::s_maxStackHeight) {
StackStats::s_maxStackHeight = height;
needToLog = true;
}
// Update the checkpoint diff stats:
int diff = last - current;
if (!isGrowingDownward)
diff = -diff;
if (diff > StackStats::s_maxCheckPointDiff) {
StackStats::s_maxCheckPointDiff = diff;
needToLog = true;
}
#if ENABLE(VERBOSE_STACK_STATS)
needToLog = true; // always log.
#endif
if (needToLog)
dataLogF(" PROBE %p diff %d/%.1fk/max %.1fk | reentry %d/max %d | height %.1fk/max %.1fk | stack %p size %.1fk\n",
current, diff, diff / 1024.0, StackStats::s_maxCheckPointDiff / 1024.0,
t.m_reentryDepth, StackStats::s_maxReentryDepth,
height / 1024.0, StackStats::s_maxStackHeight / 1024.0,
stack.origin(), stack.size() / 1024.0);
}
StackStats::LayoutCheckPoint::LayoutCheckPoint()
{
// While a layout checkpoint is not necessarily a checkpoint where we
// we will do a recursion check, it is a convenient spot for doing a
// probe to measure the height of stack usage.
//
// We'll do this probe before we commence with the layout checkpoint.
// This is because the probe also locks the sharedLock. By calling the
// probe first, we can avoid re-entering the lock.
StackStats::probe();
std::lock_guard<Lock> lock(StackStats::s_sharedMutex);
Thread& thread = Thread::current();
StackStats::PerThreadStats& t = thread.stackStats();
const StackBounds& stack = thread.stack();
bool isGrowingDownward = stack.isGrowingDownward();
// Push this checkpoint:
m_prev = StackStats::s_topLayoutCheckPoint;
if (m_prev)
m_depth = m_prev->m_depth + 1;
else {
StackStats::s_firstLayoutCheckPoint = this;
m_depth = 0;
}
StackStats::s_topLayoutCheckPoint = this;
//
char* current = reinterpret_cast<char*>(this);
char* last = reinterpret_cast<char*>(m_prev);
char* root = reinterpret_cast<char*>(StackStats::s_firstLayoutCheckPoint);
bool needToLog = false;
int diff = last - current;
if (!last)
diff = 0;
int totalDiff = root - current;
if (!root)
totalDiff = 0;
// Update the stack height stats:
int height = t.m_stackStart - current;
if (!isGrowingDownward)
height = -height;
if (height > StackStats::s_maxStackHeight) {
StackStats::s_maxStackHeight = height;
needToLog = true;
}
// Update the layout checkpoint diff stats:
if (!isGrowingDownward)
diff = -diff;
if (diff > StackStats::s_maxLayoutCheckPointDiff) {
StackStats::s_maxLayoutCheckPointDiff = diff;
needToLog = true;
}
// Update the total layout checkpoint diff stats:
if (!isGrowingDownward)
totalDiff = -totalDiff;
if (totalDiff > StackStats::s_maxTotalLayoutCheckPointDiff) {
StackStats::s_maxTotalLayoutCheckPointDiff = totalDiff;
needToLog = true;
}
#if ENABLE(VERBOSE_STACK_STATS)
needToLog = true; // always log.
#endif
if (needToLog)
dataLogF(" LAYOUT %p diff %d/%.1fk/max %.1fk | reentry %d/max %d | height %.1fk/max %.1fk | stack %p size %.1fk\n",
current, diff, diff / 1024.0, StackStats::s_maxLayoutCheckPointDiff / 1024.0,
m_depth, StackStats::s_maxLayoutReentryDepth,
totalDiff / 1024.0, StackStats::s_maxTotalLayoutCheckPointDiff / 1024.0,
stack.origin(), stack.size() / 1024.0);
}
StackStats::LayoutCheckPoint::~LayoutCheckPoint()
{
std::lock_guard<Lock> lock(StackStats::s_sharedMutex);
// Pop to the previous layout checkpoint:
StackStats::s_topLayoutCheckPoint = m_prev;
if (!m_depth)
StackStats::s_firstLayoutCheckPoint = 0;
}
} // namespace WTF
#endif // ENABLE(STACK_STATS)