421 lines
19 KiB
C#
421 lines
19 KiB
C#
|
using System;
|
||
|
|
using System.Globalization;
|
||
|
|
using System.Web;
|
||
|
|
using System.Web.Util;
|
||
|
|
using System.Threading;
|
||
|
|
using System.Diagnostics;
|
||
|
|
using System.Diagnostics.CodeAnalysis;
|
||
|
|
using Debug = System.Web.Util.Debug;
|
||
|
|
|
||
|
|
//
|
||
|
|
// Welcome to the CacheManager class, CM for short. CM monitors private bytes for the
|
||
|
|
// worker process. If the Private Bytes limit is about to be exceeded, CM will trim
|
||
|
|
// the cache (as necessary), and induce a GC to prevent the process from recycling.
|
||
|
|
//
|
||
|
|
// A timer thread is used to monitor Private Bytes. The interval is adjusted depending
|
||
|
|
// on the current memory pressure. The maximum interval is every 2 minutes, and the
|
||
|
|
// minimum interval is every 5 seconds.
|
||
|
|
//
|
||
|
|
|
||
|
|
namespace System.Web.Hosting {
|
||
|
|
internal class CacheManager: IDisposable {
|
||
|
|
const int HIGH_FREQ_INTERVAL_S = 5;
|
||
|
|
const int HIGH_FREQ_INTERVAL_MS = 5 * Msec.ONE_SECOND;
|
||
|
|
const int MEDIUM_FREQ_INTERVAL_S = 30;
|
||
|
|
const int MEDIUM_FREQ_INTERVAL_MS = 30 * Msec.ONE_SECOND;
|
||
|
|
const int LOW_FREQ_INTERVAL_S = 120;
|
||
|
|
const int LOW_FREQ_INTERVAL_MS = 120 * Msec.ONE_SECOND;
|
||
|
|
const int MEGABYTE_SHIFT = 20;
|
||
|
|
const long MEGABYTE = 1L << MEGABYTE_SHIFT; // 1048576
|
||
|
|
const int SAMPLE_COUNT = 2;
|
||
|
|
const int DELTA_SAMPLE_COUNT = 10;
|
||
|
|
|
||
|
|
private ApplicationManager _appManager;
|
||
|
|
|
||
|
|
private long _totalCacheSize;
|
||
|
|
private long _trimDurationTicks;
|
||
|
|
private int _lastTrimPercent = 10; // starts at 10, but changes to fit workload
|
||
|
|
private long _inducedGCMinInterval = TimeSpan.TicksPerSecond * 5; // starts at 5 seconds, but changes to fit workload
|
||
|
|
private DateTime _inducedGCFinishTime = DateTime.MinValue;
|
||
|
|
private long _inducedGCDurationTicks;
|
||
|
|
private int _inducedGCCount;
|
||
|
|
private long _inducedGCPostPrivateBytes;
|
||
|
|
private long _inducedGCPrivateBytesChange;
|
||
|
|
|
||
|
|
private int _currentPollInterval = MEDIUM_FREQ_INTERVAL_MS;
|
||
|
|
private DateTime _timerSuspendTime = DateTime.MinValue;
|
||
|
|
private int _inPBytesMonitorThread;
|
||
|
|
private Timer _timer;
|
||
|
|
private Object _timerLock = new object();
|
||
|
|
|
||
|
|
private long _limit; // the "effective" worker process Private Bytes limit
|
||
|
|
private long _highPressureMark;
|
||
|
|
private long _mediumPressureMark;
|
||
|
|
private long _lowPressureMark;
|
||
|
|
private long[] _deltaSamples; // a history of the increase in private bytes per second
|
||
|
|
private int _idxDeltaSamples;
|
||
|
|
private long _maxDelta; // the maximum expected increase in private bytes per second
|
||
|
|
private long _minMaxDelta; // _maxDelta must always be at least this large
|
||
|
|
private long[] _samples; // a history of the sample values (private bytes for the process)
|
||
|
|
private DateTime[] _sampleTimes; // time at which samples were taken
|
||
|
|
private int _idx;
|
||
|
|
|
||
|
|
private bool _useGetProcessMemoryInfo;
|
||
|
|
private uint _pid;
|
||
|
|
private bool _disposed;
|
||
|
|
|
||
|
|
private CacheManager() {}
|
||
|
|
|
||
|
|
internal CacheManager(ApplicationManager appManager, long privateBytesLimit) {
|
||
|
|
#if PERF
|
||
|
|
SafeNativeMethods.OutputDebugString(String.Format("Creating CacheManager with PrivateBytesLimit = {0:N}\n", privateBytesLimit));
|
||
|
|
#endif
|
||
|
|
// don't create timer if there's no memory limit
|
||
|
|
if (privateBytesLimit <= 0) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
_appManager = appManager;
|
||
|
|
_limit = privateBytesLimit;
|
||
|
|
|
||
|
|
_pid = (uint) SafeNativeMethods.GetCurrentProcessId();
|
||
|
|
|
||
|
|
// the initial expected maximum increase in private bytes is 2MB per second per CPU
|
||
|
|
_minMaxDelta = 2 * MEGABYTE * SystemInfo.GetNumProcessCPUs();
|
||
|
|
AdjustMaxDeltaAndPressureMarks(_minMaxDelta);
|
||
|
|
|
||
|
|
_samples = new long[SAMPLE_COUNT];
|
||
|
|
_sampleTimes = new DateTime[SAMPLE_COUNT];
|
||
|
|
_useGetProcessMemoryInfo = (VersionInfo.ExeName == "w3wp");
|
||
|
|
_deltaSamples = new long[DELTA_SAMPLE_COUNT];
|
||
|
|
|
||
|
|
// start timer with initial poll interval
|
||
|
|
_timer = new Timer(new TimerCallback(this.PBytesMonitorThread), null, _currentPollInterval, _currentPollInterval);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void Adjust() {
|
||
|
|
// not thread-safe, only invoke from timer callback
|
||
|
|
Debug.Assert(_inPBytesMonitorThread == 1);
|
||
|
|
|
||
|
|
Debug.Assert(SAMPLE_COUNT == 2);
|
||
|
|
// current sample
|
||
|
|
long s2 = _samples[_idx];
|
||
|
|
// previous sample
|
||
|
|
long s1 = _samples[_idx ^ 1];
|
||
|
|
|
||
|
|
// adjust _maxDelta and pressure marks
|
||
|
|
if (s2 > s1 && s1 > 0) {
|
||
|
|
// current time
|
||
|
|
DateTime d2 = _sampleTimes[_idx];
|
||
|
|
// previous time
|
||
|
|
DateTime d1 = _sampleTimes[_idx ^ 1];
|
||
|
|
|
||
|
|
long numBytes = s2 - s1;
|
||
|
|
long numSeconds = (long)Math.Round(d2.Subtract(d1).TotalSeconds);
|
||
|
|
if (numSeconds > 0) {
|
||
|
|
long delta = numBytes / numSeconds;
|
||
|
|
_deltaSamples[_idxDeltaSamples] = delta;
|
||
|
|
_idxDeltaSamples = (_idxDeltaSamples + 1) % DELTA_SAMPLE_COUNT;
|
||
|
|
// update rate of change in private bytes and pressure marks
|
||
|
|
AdjustMaxDeltaAndPressureMarks(delta);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
lock (_timerLock) {
|
||
|
|
if (_timer == null) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// adjust timer frequency
|
||
|
|
if (s2 > _mediumPressureMark) {
|
||
|
|
if (_currentPollInterval > HIGH_FREQ_INTERVAL_MS) {
|
||
|
|
_currentPollInterval = HIGH_FREQ_INTERVAL_MS;
|
||
|
|
_timer.Change(_currentPollInterval, _currentPollInterval);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else if (s2 > _lowPressureMark) {
|
||
|
|
if (_currentPollInterval > MEDIUM_FREQ_INTERVAL_MS) {
|
||
|
|
_currentPollInterval = MEDIUM_FREQ_INTERVAL_MS;
|
||
|
|
_timer.Change(_currentPollInterval, _currentPollInterval);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
if (_currentPollInterval != LOW_FREQ_INTERVAL_MS) {
|
||
|
|
_currentPollInterval = LOW_FREQ_INTERVAL_MS;
|
||
|
|
_timer.Change(_currentPollInterval, _currentPollInterval);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void AdjustMaxDeltaAndPressureMarks(long delta) {
|
||
|
|
// not thread-safe...only invoke from ctor or timer callback
|
||
|
|
Debug.Assert(_inPBytesMonitorThread == 1 || _timer == null);
|
||
|
|
|
||
|
|
// The value of _maxDelta is the largest rate of change we've seen,
|
||
|
|
// but it is reduced if the rate is now consistently less than what
|
||
|
|
// it once was.
|
||
|
|
long newMaxDelta = _maxDelta;
|
||
|
|
if (delta > newMaxDelta) {
|
||
|
|
// set maxDelta to the current rate of change
|
||
|
|
newMaxDelta = delta;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
// if _maxDelta is at least four times larger than every sample rate in the history,
|
||
|
|
// then reduce _maxDelta
|
||
|
|
bool reduce = true;
|
||
|
|
long maxDelta = _maxDelta / 4;
|
||
|
|
foreach (long rate in _deltaSamples) {
|
||
|
|
if (rate > maxDelta) {
|
||
|
|
reduce = false;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (reduce) {
|
||
|
|
newMaxDelta = maxDelta * 2;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// ensure that maxDelta is sufficiently large so that the _highPressureMark is sufficiently
|
||
|
|
// far away from the memory limit
|
||
|
|
newMaxDelta = Math.Max(newMaxDelta, _minMaxDelta);
|
||
|
|
|
||
|
|
// Do we have a new maxDelta? If so, adjust it and pressure marks.
|
||
|
|
if (_maxDelta != newMaxDelta) {
|
||
|
|
// adjust _maxDelta
|
||
|
|
_maxDelta = newMaxDelta;
|
||
|
|
// instead of using _maxDelta, use twice _maxDelta since recycling is
|
||
|
|
// expensive and the real delta fluctuates
|
||
|
|
_highPressureMark = Math.Max(_limit * 9 / 10, _limit - (_maxDelta * 2 * HIGH_FREQ_INTERVAL_S));
|
||
|
|
_lowPressureMark = Math.Max(_limit * 6 / 10, _limit - (_maxDelta * 2 * LOW_FREQ_INTERVAL_S));
|
||
|
|
_mediumPressureMark = Math.Max((_highPressureMark + _lowPressureMark) / 2 , _limit - (_maxDelta * 2 * MEDIUM_FREQ_INTERVAL_S));
|
||
|
|
_mediumPressureMark = Math.Min(_highPressureMark , _mediumPressureMark);
|
||
|
|
|
||
|
|
#if PERF
|
||
|
|
SafeNativeMethods.OutputDebugString(String.Format("CacheManager.AdjustMaxDeltaAndPressureMarks: _highPressureMark={0:N}, _mediumPressureMark={1:N}, _lowPressureMark={2:N}, _maxDelta={3:N}\n", _highPressureMark, _mediumPressureMark, _lowPressureMark, _maxDelta));
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#if DBG
|
||
|
|
Debug.Trace("CacheMemory", "AdjustMaxDeltaAndPressureMarks "
|
||
|
|
+ "delta=" + delta
|
||
|
|
+ ", _maxDelta=" + _maxDelta
|
||
|
|
+ ", _highPressureMark=" + _highPressureMark
|
||
|
|
+ ", _mediumPressureMark=" + _mediumPressureMark
|
||
|
|
+ ", _lowPressureMark=" + _lowPressureMark);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
[SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods", Justification="Need to call GC.Collect.")]
|
||
|
|
private void CollectInfrequently(long privateBytes) {
|
||
|
|
// not thread-safe, only invoke from timer callback
|
||
|
|
Debug.Assert(_inPBytesMonitorThread == 1);
|
||
|
|
|
||
|
|
// The Server GC on x86 can traverse ~200mb per CPU per second, and the maximum heap size
|
||
|
|
// is about 3400mb, so the worst case scenario on x86 would take about 8 seconds to collect
|
||
|
|
// on a dual CPU box.
|
||
|
|
//
|
||
|
|
// The Server GC on x64 can traverse ~300mb per CPU per second, so a 6000 MB heap will take
|
||
|
|
// about 10 seconds to collect on a dual CPU box. The worst case scenario on x64 would make
|
||
|
|
// you want to return your hardware for a refund.
|
||
|
|
|
||
|
|
long timeSinceInducedGC = DateTime.UtcNow.Subtract(_inducedGCFinishTime).Ticks;
|
||
|
|
bool infrequent = (timeSinceInducedGC > _inducedGCMinInterval);
|
||
|
|
|
||
|
|
// if we haven't collected recently, or if the trim percent is low (less than 50%),
|
||
|
|
// we need to collect again
|
||
|
|
if (infrequent || _lastTrimPercent < 50) {
|
||
|
|
|
||
|
|
// if we're inducing GC too frequently, increase the trim percentage, but don't go above 50%
|
||
|
|
if (!infrequent) {
|
||
|
|
_lastTrimPercent = Math.Min(50, _lastTrimPercent + 10);
|
||
|
|
}
|
||
|
|
// if we're inducing GC infrequently, we may want to decrease the trim percentage
|
||
|
|
else if (_lastTrimPercent > 10 && timeSinceInducedGC > 2 * _inducedGCMinInterval) {
|
||
|
|
_lastTrimPercent = Math.Max(10, _lastTrimPercent - 10);
|
||
|
|
}
|
||
|
|
int percent = (_totalCacheSize > 0) ? _lastTrimPercent : 0;
|
||
|
|
long trimmedOrExpired = 0;
|
||
|
|
if (percent > 0) {
|
||
|
|
Stopwatch sw1 = Stopwatch.StartNew();
|
||
|
|
trimmedOrExpired = _appManager.TrimCaches(percent);
|
||
|
|
sw1.Stop();
|
||
|
|
_trimDurationTicks = sw1.Elapsed.Ticks;
|
||
|
|
}
|
||
|
|
|
||
|
|
//
|
||
|
|
|
||
|
|
if (trimmedOrExpired == 0 || _appManager.ShutdownInProgress) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// collect and record statistics
|
||
|
|
Stopwatch sw2 = Stopwatch.StartNew();
|
||
|
|
GC.Collect();
|
||
|
|
sw2.Stop();
|
||
|
|
|
||
|
|
_inducedGCCount++; // only used for debugging
|
||
|
|
_inducedGCFinishTime = DateTime.UtcNow;
|
||
|
|
_inducedGCDurationTicks = sw2.Elapsed.Ticks;
|
||
|
|
_inducedGCPostPrivateBytes = NextSample();
|
||
|
|
_inducedGCPrivateBytesChange = privateBytes - _inducedGCPostPrivateBytes;
|
||
|
|
// target 3.3% Time in GC, but don't induce a GC more than once every 5 seconds
|
||
|
|
// Notes on calculation below: If G is duration of garbage collection and T is duration
|
||
|
|
// between starting the next collection, then G/T is % Time in GC. If we target 3.3%,
|
||
|
|
// then G/T = 3.3% = 33/1000, so T = G * 1000/33.
|
||
|
|
_inducedGCMinInterval = Math.Max(_inducedGCDurationTicks * 1000 / 33, 5 * TimeSpan.TicksPerSecond);
|
||
|
|
// no more frequently than every 60 seconds if change is less than 1%
|
||
|
|
if (_inducedGCPrivateBytesChange * 100 <= privateBytes) {
|
||
|
|
_inducedGCMinInterval = Math.Max(_inducedGCMinInterval, 60 * TimeSpan.TicksPerSecond);
|
||
|
|
}
|
||
|
|
#if DBG
|
||
|
|
Debug.Trace("CacheMemory", "GC.COLLECT STATS "
|
||
|
|
+ "TrimCaches(" + percent + ")"
|
||
|
|
+ ", trimDurationSeconds=" + (_trimDurationTicks/TimeSpan.TicksPerSecond)
|
||
|
|
+ ", trimmedOrExpired=" + trimmedOrExpired
|
||
|
|
+ ", #secondsSinceInducedGC=" + (timeSinceInducedGC/TimeSpan.TicksPerSecond)
|
||
|
|
+ ", InducedGCCount=" + _inducedGCCount
|
||
|
|
+ ", gcDurationSeconds=" + (_inducedGCDurationTicks/TimeSpan.TicksPerSecond)
|
||
|
|
+ ", PrePrivateBytes=" + privateBytes
|
||
|
|
+ ", PostPrivateBytes=" + _inducedGCPostPrivateBytes
|
||
|
|
+ ", PrivateBytesChange=" + _inducedGCPrivateBytesChange
|
||
|
|
+ ", gcMinIntervalSeconds=" + (_inducedGCMinInterval/TimeSpan.TicksPerSecond));
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#if PERF
|
||
|
|
SafeNativeMethods.OutputDebugString(" ** COLLECT **: "
|
||
|
|
+ percent + "%, "
|
||
|
|
+ (_trimDurationTicks/TimeSpan.TicksPerSecond) + " seconds"
|
||
|
|
+ ", infrequent=" + infrequent
|
||
|
|
+ ", removed=" + trimmedOrExpired
|
||
|
|
+ ", sinceIGC=" + (timeSinceInducedGC/TimeSpan.TicksPerSecond)
|
||
|
|
+ ", IGCCount=" + _inducedGCCount
|
||
|
|
+ ", IGCDuration=" + (_inducedGCDurationTicks/TimeSpan.TicksPerSecond)
|
||
|
|
+ ", preBytes=" + privateBytes
|
||
|
|
+ ", postBytes=" + _inducedGCPostPrivateBytes
|
||
|
|
+ ", byteChange=" + _inducedGCPrivateBytesChange
|
||
|
|
+ ", IGCMinInterval=" + (_inducedGCMinInterval/TimeSpan.TicksPerSecond) + "\n");
|
||
|
|
#endif
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
internal long GetUpdatedTotalCacheSize(long sizeUpdate) {
|
||
|
|
if (sizeUpdate != 0) {
|
||
|
|
long totalSize = Interlocked.Add(ref _totalCacheSize, sizeUpdate);
|
||
|
|
#if PERF
|
||
|
|
SafeNativeMethods.OutputDebugString("CacheManager.GetUpdatedTotalCacheSize:"
|
||
|
|
+ " _totalCacheSize= " + totalSize
|
||
|
|
+ ", sizeUpdate=" + sizeUpdate + "\n");
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return totalSize;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return _totalCacheSize;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public void Dispose() {
|
||
|
|
_disposed = true;
|
||
|
|
Dispose(true);
|
||
|
|
GC.SuppressFinalize(this);
|
||
|
|
}
|
||
|
|
|
||
|
|
protected virtual void Dispose(bool disposing) {
|
||
|
|
if (disposing) {
|
||
|
|
// managed and unmanaged resources can be touched/released
|
||
|
|
DisposeTimer();
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
// the finalizer is calling, so don't touch managed state
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private void DisposeTimer() {
|
||
|
|
lock (_timerLock) {
|
||
|
|
if (_timer != null) {
|
||
|
|
_timer.Dispose();
|
||
|
|
_timer = null;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private void PBytesMonitorThread(object state) {
|
||
|
|
// callbacks are queued and can unleash all at once, so concurrent invocations must be prevented
|
||
|
|
if (Interlocked.Exchange(ref _inPBytesMonitorThread, 1) != 0)
|
||
|
|
return;
|
||
|
|
|
||
|
|
try {
|
||
|
|
if (_disposed) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
#if DBG
|
||
|
|
Debug.Trace("CacheMemory", "\r\n\r\n***BEG** PBytesMonitorThread " + DateTime.Now.ToString("T", CultureInfo.InvariantCulture));
|
||
|
|
#endif
|
||
|
|
// get another sample
|
||
|
|
long privateBytes = NextSample();
|
||
|
|
|
||
|
|
// adjust frequency of timer and pressure marks after the sample is captured
|
||
|
|
Adjust();
|
||
|
|
|
||
|
|
if (privateBytes > _highPressureMark) {
|
||
|
|
// induce a GC if necessary
|
||
|
|
CollectInfrequently(privateBytes);
|
||
|
|
}
|
||
|
|
|
||
|
|
#if DBG
|
||
|
|
Debug.Trace("CacheMemory", "**END** PBytesMonitorThread "
|
||
|
|
+ "privateBytes=" + privateBytes
|
||
|
|
+ ", _highPressureMark=" + _highPressureMark);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
}
|
||
|
|
finally {
|
||
|
|
Interlocked.Exchange(ref _inPBytesMonitorThread, 0);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private long NextSample() {
|
||
|
|
// not thread-safe, only invoke from timer callback
|
||
|
|
Debug.Assert(_inPBytesMonitorThread == 1);
|
||
|
|
|
||
|
|
// NtQuerySystemInformation is a very expensive call. A new function
|
||
|
|
// exists on XP Pro and later versions of the OS and it performs much
|
||
|
|
// better. The name of that function is GetProcessMemoryInfo. For hosting
|
||
|
|
// scenarios where a larger number of w3wp.exe instances are running, we
|
||
|
|
// want to use the new API (VSWhidbey 417366).
|
||
|
|
long privateBytes;
|
||
|
|
if (_useGetProcessMemoryInfo) {
|
||
|
|
long privatePageCount;
|
||
|
|
UnsafeNativeMethods.GetPrivateBytesIIS6(out privatePageCount, true /*nocache*/);
|
||
|
|
privateBytes = privatePageCount;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
uint dummy;
|
||
|
|
uint privatePageCount = 0;
|
||
|
|
// this is a very expensive call
|
||
|
|
UnsafeNativeMethods.GetProcessMemoryInformation(_pid, out privatePageCount, out dummy, true /*nocache*/);
|
||
|
|
privateBytes = (long)privatePageCount << MEGABYTE_SHIFT;
|
||
|
|
}
|
||
|
|
|
||
|
|
// increment the index (it's either 1 or 0)
|
||
|
|
Debug.Assert(SAMPLE_COUNT == 2);
|
||
|
|
_idx = _idx ^ 1;
|
||
|
|
// remember the sample time
|
||
|
|
_sampleTimes[_idx] = DateTime.UtcNow;
|
||
|
|
// remember the sample value
|
||
|
|
_samples[_idx] = privateBytes;
|
||
|
|
|
||
|
|
#if PERF
|
||
|
|
SafeNativeMethods.OutputDebugString(String.Format("CacheManager.NextSample: privateBytes={0:N}, _highPresureMark={1:N}\n", privateBytes, _highPressureMark));
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return privateBytes;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|