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perf: limit JavaStringCache entries to deal with excessive GREF counts #18956

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merged 3 commits into from
Nov 29, 2024
Merged

perf: limit JavaStringCache entries to deal with excessive GREF counts #18956

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deff175
perf: limit JavaStringCache entries to deal with excessive GREF counts
ramezgerges Nov 28, 2024
3fc4fec
chore: add TextBlock FeatureConfiguration options
ramezgerges Nov 29, 2024
cce9701
chore: keep using fast path even when !IsJavaStringCachedEnabled
ramezgerges Nov 29, 2024
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124 changes: 64 additions & 60 deletions src/Uno.UI/UI/Xaml/Controls/TextBlock/JavaStringCache.Android.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,33 +3,33 @@
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Text;
using Windows.Foundation;

using Uno;
using Uno.Extensions;
using Uno.UI;
using Uno.Foundation.Logging;
using Microsoft.UI.Xaml.Media;
using Uno.Collections;
using Android.Security.Keystore;
using Java.Security;
using Uno.Buffers;
using Windows.System;

namespace Microsoft.UI.Xaml.Controls
{
/// <summary>
/// A TextBlock measure cache for non-formatted text.
/// A cache for native java strings. This cache periodically evicts entries that haven't been used
/// in a while. Additionally, it also evicts the least recently used entries when adding new entries beyond a certain
/// capacity. Limiting the total capacity is necessary to
/// </summary>
internal static class JavaStringCache
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{
private static Logger _log = typeof(JavaStringCache).Log();
private static Stopwatch _watch = Stopwatch.StartNew();
private static HashtableEx _table = new();
// Xamarin.Android uses Android global references to provide mappings between Java instances and the associated managed instances, as when invoking a Java method a Java instance needs to be provided to Java.
// Unfortunately, Android emulators only allow 2000 global references to exist at a time. Hardware has a much higher limit of 52000 global references. The lower limit can be problematic when running applications on the emulator, so knowing where the instance came from can be very useful.
// https://github.com/MicrosoftDocs/xamarin-docs/blob/live/docs/android/troubleshooting/troubleshooting.md
// https://github.com/unoplatform/uno/issues/18951
private const int MaxEntryCount = 1000;
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private static readonly Logger _log = typeof(JavaStringCache).Log();
private static readonly Stopwatch _watch = Stopwatch.StartNew();
private static readonly Dictionary<string, LinkedListNode<KeyEntry>> _table = new();
private static readonly LinkedList<KeyEntry> _queue = new();
private static readonly object _gate = new();

private static TimeSpan _lastScavenge;
private static object _gate = new();

internal static readonly TimeSpan LowMemoryTrimInterval = TimeSpan.FromMinutes(5);
internal static readonly TimeSpan MediumMemoryTrimInterval = TimeSpan.FromMinutes(3);
Expand All @@ -38,21 +38,32 @@ internal static class JavaStringCache

internal static readonly TimeSpan ScavengeInterval = TimeSpan.FromMinutes(.5);

private static DefaultArrayPoolPlatformProvider _platformProvider = new DefaultArrayPoolPlatformProvider();
private static readonly DefaultArrayPoolPlatformProvider _platformProvider = new DefaultArrayPoolPlatformProvider();

/// <summary>Determines if automatic memory management is enabled</summary>
private static readonly bool _automaticManagement;
/// <summary>Determines if GC trim callback has been registerd if non-zero</summary>
private static int _trimCallbackCreated;

private record KeyEntry(string Value, Java.Lang.String NativeValue)
{
public TimeSpan LastUse { get; set; } = _watch.Elapsed;
}
private readonly record struct KeyEntry(string CsString, Java.Lang.String JavaString, TimeSpan LastUse);

static JavaStringCache()
{
_automaticManagement = WinRTFeatureConfiguration.ArrayPool.EnableAutomaticMemoryManagement && _platformProvider.CanUseMemoryManager;
if (_automaticManagement)
{
if (_log.IsEnabled(LogLevel.Debug))
{
_log.Debug($"Using automatic memory management");
}

_platformProvider.RegisterTrimCallback(_ => Trim(), _gate);
}
else
{
if (_log.IsEnabled(LogLevel.Debug))
{
_log.Debug($"Using manual memory management");
}
}
}

/// <summary>
Expand All @@ -62,64 +73,60 @@ static JavaStringCache()
/// <returns></returns>
public static Java.Lang.String GetNativeString(string value)
{
TryInitializeMemoryManagement();

Scavenge();

lock (_gate)
{
if (_table.TryGetValue(value, out var result) && result is KeyEntry entry)
if (_table.TryGetValue(value, out var result))
{
if (_log.IsEnabled(LogLevel.Trace))
{
_log.Trace($"Reusing native string: [{value}]");
}

entry.LastUse = _watch.Elapsed;
return entry.NativeValue;
var entry = result.Value;
result.Value = entry with { LastUse = _watch.Elapsed };
_queue.Remove(result);
_queue.AddFirst(result);

return entry.JavaString;
}
else
{
if (_queue.Count == MaxEntryCount)
{
var last = _queue.Last!.Value.CsString;
_table.Remove(last);
_queue.RemoveLast();

if (_log.IsEnabled(LogLevel.Trace))
{
_log.Trace($"{nameof(JavaStringCache)} is full. Evicting [{last}]");
}
}

if (_log.IsEnabled(LogLevel.Trace))
{
_log.Trace($"Creating native string for [{value}]");
}

var javaString = new Java.Lang.String(value);
_table[value] = new KeyEntry(value, javaString);
var node = new LinkedListNode<KeyEntry>(new KeyEntry(value, javaString, _watch.Elapsed));
_queue.AddFirst(node);
_table[value] = node;
return javaString;
}
}
}

private static void TryInitializeMemoryManagement()
{
if (_automaticManagement && Interlocked.Exchange(ref _trimCallbackCreated, 1) == 0)
{
if (_log.IsEnabled(LogLevel.Debug))
{
_log.Debug($"Using automatic memory management");
}

_platformProvider.RegisterTrimCallback(_ => Trim(), _gate);
}
else
{
if (_log.IsEnabled(LogLevel.Debug))
{
_log.Debug($"Using manual memory management");
}
}
}

private static bool Trim()
{
if (!_automaticManagement)
{
return false;
}

var threshold = _platformProvider?.AppMemoryUsageLevel switch
var threshold = _platformProvider.AppMemoryUsageLevel switch
{
AppMemoryUsageLevel.Low => LowMemoryTrimInterval,
AppMemoryUsageLevel.Medium => MediumMemoryTrimInterval,
Expand All @@ -130,7 +137,7 @@ private static bool Trim()

if (_log.IsEnabled(LogLevel.Trace))
{
_log.Trace($"Memory pressure is {_platformProvider?.AppMemoryUsageLevel}, using trim interval of {threshold}");
_log.Trace($"Memory pressure is {_platformProvider.AppMemoryUsageLevel}, using trim interval of {threshold}");
}

Trim(threshold);
Expand All @@ -154,26 +161,23 @@ private static void Trim(TimeSpan interval)
{
lock (_gate)
{
List<string>? entries = null;
int trimmedCount = 0;
foreach (var entry in _table.Values)
{
if (entry is KeyEntry keyEntry && keyEntry.LastUse + interval < _watch.Elapsed)
var node = entry.Value;
if (node.LastUse + interval < _watch.Elapsed)
{
entries ??= new();
entries.Add(keyEntry.Value);
_table.Remove(node.CsString);
_queue.Remove(node);
trimmedCount++;
}
}

if (entries is not null)
if (trimmedCount > 0)
{
if (_log.IsEnabled(LogLevel.Debug))
{
_log.Debug($"Trimming {entries.Count} native strings unused since {interval}");
}

foreach (var entry in entries)
{
_table.Remove(entry);
_log.Debug($"Trimming {trimmedCount} native strings unused since {interval}");
}
}
else
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