Remove unnecessary spills from BufferedStream.ReadAsync (#55190)

dotnet · Jul 6, 2021 · d25af09 · d25af09
1 parent 7e43f8c
commit d25af09
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/BufferedStream.cs b/src/libraries/System.Private.CoreLib/src/System/IO/BufferedStream.cs
@@ -730,7 +730,7 @@ public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken
                 // If the requested read is larger than buffer size, avoid the buffer and still use a single read:
                 if (buffer.Length >= _bufferSize)
                 {
-                    return bytesAlreadySatisfied + await _stream.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
+                    return await _stream.ReadAsync(buffer, cancellationToken).ConfigureAwait(false) + bytesAlreadySatisfied;
                 }
 
                 // Ok. We can fill the buffer:

diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/BufferedFileStreamStrategy.cs b/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/BufferedFileStreamStrategy.cs
@@ -472,7 +472,7 @@ private async ValueTask<int> ReadAsyncSlowPath(Task semaphoreLockTask, Memory<by
                 // If the requested read is larger than buffer size, avoid the buffer and still use a single read:
                 if (buffer.Length >= _bufferSize)
                 {
-                    return bytesAlreadySatisfied + await _strategy.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
+                    return await _strategy.ReadAsync(buffer, cancellationToken).ConfigureAwait(false) + bytesAlreadySatisfied;
                 }
 
                 // Ok. We can fill the buffer: