Skip to content

Eliminate races during LRU warmup #457

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 10 commits into from
Nov 11, 2023
Merged

Eliminate races during LRU warmup #457

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
e93ca3f
thru
Nov 10, 2023
02d2316
lock
Nov 10, 2023
5c99171
debug view
Nov 10, 2023
c4f1f9d
bounded
Nov 10, 2023
408ca66
use counter
Nov 10, 2023
5d2bd9e
fix cold counter
Nov 10, 2023
f44e27f
stable warm
Nov 10, 2023
1b13f82
merge
Nov 10, 2023
ccad565
align tests
Nov 10, 2023
fd53062
tlru tests
Nov 10, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 9 additions & 6 deletions BitFaster.Caching.UnitTests/Lru/ConcurrentLruTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -562,11 +562,10 @@ public void WhenValueExpiresItIsDisposed()
lruOfDisposable.GetOrAdd(i, disposableValueFactory.Create);
}

disposableValueFactory.Items[0].IsDisposed.Should().BeFalse();
disposableValueFactory.Items[1].IsDisposed.Should().BeFalse();

disposableValueFactory.Items[2].IsDisposed.Should().BeTrue();
disposableValueFactory.Items[0].IsDisposed.Should().BeTrue();

disposableValueFactory.Items[1].IsDisposed.Should().BeFalse();
disposableValueFactory.Items[2].IsDisposed.Should().BeFalse();
disposableValueFactory.Items[3].IsDisposed.Should().BeFalse();
disposableValueFactory.Items[4].IsDisposed.Should().BeFalse();
disposableValueFactory.Items[5].IsDisposed.Should().BeFalse();
Expand Down Expand Up @@ -598,8 +597,8 @@ public void WhenValueEvictedItemRemovedEventIsFired()

removedItems.Count.Should().Be(2);

removedItems[0].Key.Should().Be(3);
removedItems[0].Value.Should().Be(4);
removedItems[0].Key.Should().Be(1);
removedItems[0].Value.Should().Be(2);
removedItems[0].Reason.Should().Be(ItemRemovedReason.Evicted);

removedItems[1].Key.Should().Be(4);
Expand Down Expand Up @@ -1016,6 +1015,8 @@ public void WhenTrimCountIsMoreThanCapacityThrows()
[InlineData(9, new int[] { })]
public void WhenColdItemsExistTrimRemovesExpectedItemCount(int trimCount, int[] expected)
{
Warmup();

// initial state:
// Hot = 9, 8, 7
// Warm = 3, 2, 1
Expand Down Expand Up @@ -1109,6 +1110,8 @@ public void WhenHotItemsExistTrimRemovesExpectedItemCount(int itemCount, int[] e
[InlineData(9, new int[] { })]
public void WhenColdItemsAreTouchedTrimRemovesExpectedItemCount(int trimCount, int[] expected)
{
Warmup();

// initial state:
// Hot = 9, 8, 7
// Warm = 3, 2, 1
Expand Down
4 changes: 2 additions & 2 deletions BitFaster.Caching.UnitTests/Lru/ConcurrentTLruTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -92,8 +92,8 @@ public void WhenValueEvictedItemRemovedEventIsFired()

removedItems.Count.Should().Be(2);

removedItems[0].Key.Should().Be(3);
removedItems[0].Value.Should().Be(4);
removedItems[0].Key.Should().Be(1);
removedItems[0].Value.Should().Be(2);
removedItems[0].Reason.Should().Be(ItemRemovedReason.Evicted);

removedItems[1].Key.Should().Be(4);
Expand Down
18 changes: 6 additions & 12 deletions BitFaster.Caching/Lru/ConcurrentLruCore.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -587,20 +587,14 @@ private void CycleDuringWarmup(int hotCount)

if (this.hotQueue.TryDequeue(out var item))
{
// always move to warm until it is full
if (Volatile.Read(ref this.counter.warm) < this.capacity.Warm)
{
// If there is a race, we will potentially add multiple items to warm. Guard by cycling the queue.
int warmCount = this.Move(item, ItemDestination.Warm, ItemRemovedReason.Evicted);
CycleWarm(warmCount);
}
else
int count = this.Move(item, ItemDestination.Warm, ItemRemovedReason.Evicted);

// if warm is now full, overflow to cold and mark as warm
if (count > this.capacity.Warm)
{
// Else mark isWarm and move items to cold.
// If there is a race, we will potentially add multiple items to cold. Guard by cycling the queue.
Volatile.Write(ref this.isWarm, true);
int coldCount = this.Move(item, ItemDestination.Cold, ItemRemovedReason.Evicted);
CycleCold(coldCount);
count = LastWarmToCold();
ConstrainCold(count, ItemRemovedReason.Evicted);
}
}
else
Expand Down