批量OCR期间高峰内存

// Clamp concurrency to avoid memory saturation and CPU over-subscription.
int concurrency = Math.Clamp(Environment.ProcessorCount / 2, 1, 4);

Imports System

' Clamp concurrency to avoid memory saturation and CPU over-subscription.
Dim concurrency As Integer = Math.Clamp(Environment.ProcessorCount \ 2, 1, 4)

// Pre-create one engine per concurrent slot and reuse them across segments.
var enginePool = new ConcurrentBag<IronTesseract>(
    Enumerable.Range(0, concurrency).Select(_ => new IronTesseract())
);

' Pre-create one engine per concurrent slot and reuse them across segments.
Dim enginePool As New ConcurrentBag(Of IronTesseract)(
    Enumerable.Range(0, concurrency).Select(Function(_) New IronTesseract())
)

using var semaphore = new SemaphoreSlim(concurrency);
await semaphore.WaitAsync();
try
{
    // Rent a pre-loaded engine from the pool.
    if (!enginePool.TryTake(out var ocr))
        ocr = new IronTesseract(); // Defensive fallback; should never be reached.
    try
    {
        using var input = new OcrInput();
        input.LoadPdf(segmentStream); // page-range segment produced upstream
        var ocrResult = await ocr.ReadAsync(input);
        ocrResult.SaveAsSearchablePdf(outputPath);
    }
    finally
    {
        enginePool.Add(ocr); // Return engine to pool for the next waiting segment.
    }
}
finally
{
    semaphore.Release();
}

Imports System.Threading
Imports IronOcr

Dim semaphore As New SemaphoreSlim(concurrency)
Await semaphore.WaitAsync()
Try
    ' Rent a pre-loaded engine from the pool.
    Dim ocr As IronTesseract = Nothing
    If Not enginePool.TryTake(ocr) Then
        ocr = New IronTesseract() ' Defensive fallback; should never be reached.
    End If
    Try
        Using input As New OcrInput()
            input.LoadPdf(segmentStream) ' page-range segment produced upstream
            Dim ocrResult = Await ocr.ReadAsync(input)
            ocrResult.SaveAsSearchablePdf(outputPath)
        End Using
    Finally
        enginePool.Add(ocr) ' Return engine to pool for the next waiting segment.
    End Try
Finally
    semaphore.Release()
End Try