103 lines
3.7 KiB
C#
103 lines
3.7 KiB
C#
// -----------------------------------------------------------------------------
|
|
// file="L4.Prefetch"
|
|
// Project: StgSharp
|
|
// Copyright (c) Nitload.
|
|
// SPDX-License-Identifier: MIT
|
|
// -----------------------------------------------------------------------------
|
|
|
|
using System.ComponentModel;
|
|
using System.Numerics;
|
|
|
|
namespace StgSharp.HighPerformance.Memory
|
|
{
|
|
public unsafe partial class L4
|
|
{
|
|
|
|
private partial void Prefetch()
|
|
{
|
|
if (CurrentPredict is null) {
|
|
return;
|
|
}
|
|
IL4Predict predict = CurrentPredict;
|
|
Span<CacheLineDescription> span = new(_prediction, PredictionCount);
|
|
PredictResult result = predict.Predict(span, out int actualCount);
|
|
_exhausted = (result & PredictResult.Exhausted) != 0;
|
|
if (actualCount <= 0)
|
|
{
|
|
_exhausted = true;
|
|
return;
|
|
}
|
|
int missIndex = 0;
|
|
for (int i = 0; i < actualCount; i++)
|
|
{
|
|
ref CacheLineDescription handle = ref span[i];
|
|
nuint address = handle.Address;
|
|
if (!_map.TryGet(address, out _))
|
|
{
|
|
// miss and record
|
|
span[missIndex] = handle;
|
|
missIndex++;
|
|
}
|
|
}
|
|
|
|
// now prefetch the misses
|
|
for (int i = 0; i < missIndex; i++)
|
|
{
|
|
CacheLineMetadata* head;
|
|
ref CacheLineDescription pHandle = ref span[i];
|
|
nuint address = pHandle.Address;
|
|
int index;
|
|
if (_map.TryGet(address, out nuint handle))
|
|
{
|
|
head = (CacheLineMetadata*)handle;
|
|
index = (int)(head - _head);
|
|
_predictCount[index] = 0; // reset eviction counter
|
|
|
|
#region update predictor belonging
|
|
|
|
if (_predictCount[index] > short.MaxValue / 2)
|
|
{
|
|
int predictCount = Volatile.Read(ref _predictCount[index]);
|
|
int mapCount = Volatile.Read(ref _mapCount[index]);
|
|
int decrement = (int.Min(predictCount, mapCount) + 1) / 2;
|
|
_ = Interlocked.Add(ref _predictCount[index], -decrement);
|
|
_ = Interlocked.Add(ref _mapCount[index], -decrement);
|
|
}
|
|
_predictCount[index]++;
|
|
|
|
#endregion
|
|
|
|
continue;
|
|
}
|
|
|
|
int retryCount = 0, remain = missIndex - i;
|
|
const int maxRetry = 1024;
|
|
while (!_bufferAllocator.TryAlloc(pHandle.Size, out index))
|
|
{
|
|
remain = Evict(remain);
|
|
retryCount++;
|
|
if (retryCount > maxRetry) {
|
|
throw new OverflowException($"Failed to evict cache line after {maxRetry} retries.");
|
|
}
|
|
if (retryCount > maxRetry / 2) {
|
|
Thread.Sleep(1);
|
|
}
|
|
}
|
|
head = _head + index;
|
|
head->Origin = address;
|
|
head->CustomizeProfile = pHandle.MapPolicy;
|
|
head->RefCount = 0;
|
|
|
|
_predictCount[index] = 1;
|
|
_mapCount[index] = 1;
|
|
|
|
// pre fetch them here
|
|
predict.Prefetch(head->Origin, head->CustomizeProfile, new Span<byte>((byte*)(head->PositionMask + _baseAddress), (int)head->SizeMask));
|
|
_ = _map.TryAddOrSet(address, (nuint)head, out _);
|
|
}
|
|
_ = Interlocked.Add(ref _aheadCount, actualCount);
|
|
}
|
|
|
|
}
|
|
}
|