Dotnet Core - Performance Tuning of Applications

 🚀 How to Improve Performance in ASP.NET Core Applications

Performance optimization in .NET Core is multi-layered, covering areas from code-level tuning to infrastructure scaling.
Here’s a structured breakdown:

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🧱 1. Use Built-in Caching

🔹 Memory Cache (for small-scale, single-server)

builder.Services.AddMemoryCache();

public class ProductService
{
    private readonly IMemoryCache _cache;
    public ProductService(IMemoryCache cache) => _cache = cache;

    public Product GetProduct(int id)
    {
        return _cache.GetOrCreate($"product_{id}", entry =>
        {
            entry.SlidingExpiration = TimeSpan.FromMinutes(5);
            return LoadProductFromDb(id);
        });
    }
}

🔹 Distributed Cache (for load-balanced apps)

Use Redis, SQL Server, or AWS ElastiCache.

builder.Services.AddStackExchangeRedisCache(options =>
{
    options.Configuration = "localhost:6379";
});

✅ Benefit: Reduces DB hits and speeds up responses.

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⚙️ 2. Enable Response Caching

Cache HTTP responses for static or infrequently changing data.

builder.Services.AddResponseCaching();
app.UseResponseCaching();

[ResponseCache(Duration = 60)]
public IActionResult GetWeather() => Ok("Sunny");

✅ Benefit: Reuses responses instead of regenerating data.

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⚡ 3. Use Asynchronous Code

ASP.NET Core is non-blocking. Always use async/await for I/O operations:

public async Task<IActionResult> GetProductsAsync() 
    => Ok(await _db.Products.ToListAsync());

✅ Benefit: Frees up threads → handles more concurrent requests.

---

🧰 4. Optimize Entity Framework Core

• Use AsNoTracking() for read-only queries.
• Fetch only needed columns via Select().
• Use compiled queries for hot paths.
• Use connection pooling.

Example:

var products = await _context.Products
    .AsNoTracking()
    .Select(p => new { p.Id, p.Name })
    .ToListAsync();

✅ Benefit: Reduces EF overhead and memory allocations.

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🧩 5. Compression & Minification

Enable Response Compression middleware:

builder.Services.AddResponseCompression();
app.UseResponseCompression();

✅ Compresses JSON, HTML, CSS, etc., reducing network load.

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💾 6. Use Data Transfer Optimization

• Use DTOs to avoid over fetching large models.
• Paginate results.
• Use gzip/brotli compression and HTTP/2.

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🌐 7. Use CDN & Static File Optimization

Host static assets (JS, CSS, images) on a CDN like CloudFront.
Also, use cache headers:

app.UseStaticFiles(new StaticFileOptions
{
    OnPrepareResponse = ctx =>
    {
        ctx.Context.Response.Headers.Append("Cache-Control", "public,max-age=604800");
    }
});

---

🧮 8. Connection & Pooling

Use IHttpClientFactory for efficient, pooled HTTP calls:

builder.Services.AddHttpClient("MyClient");

✅ Avoids socket exhaustion caused by frequent new HttpClient instances.

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🧠 9. Reduce Middleware Overhead

Register only necessary middleware, and put frequently used ones first (e.g., authentication before routing).

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🧩 10. Use Output Caching (ASP.NET Core 7+)

Output caching stores full HTTP responses:

builder.Services.AddOutputCache();
app.UseOutputCache();

[OutputCache(Duration = 60)]
public IActionResult GetProducts() => Ok(Products);

✅ Much faster than recomputing each request.

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☁️ 11. Use Cloud & Deployment Optimization (AWS Context)

On AWS, you can:

• Use Elastic Beanstalk or ECS/EKS for autoscaling.
• Add AWS ElastiCache for distributed caching.
• Use AWS CloudFront CDN.
• Add Application Load Balancer for traffic balancing.
• Store assets in S3 instead of app server.

✅ You can also enable AOT (Ahead-of-Time Compilation) for startup performance improvements.

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🧪 12. Profiling & Diagnostics

Use tools like:

• dotnet-trace, dotnet-counters
• Application Insights
• MiniProfiler
• AWS X-Ray (for distributed tracing)

✅ Identify slow methods, DB queries, or excessive GC pressure.

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🧠 13. Memory Management

• Use Span<T>, Memory<T> for high-performance code.
• Avoid large object allocations.
• Prefer pooled objects (ArrayPool<T>).
• Release disposable resources properly.

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✅ Summary Table

Area	Technique	Benefit
Caching	Memory, Redis, Output Cache	Reduce recomputation
Async I/O	async/await	Handle more requests
EF Core	AsNoTracking, Projection	Optimize DB performance
Compression	Gzip, Brotli	Reduce payload
Middleware	Optimize pipeline	Reduce latency
CDN/Static	Cache headers	Reduce load
Diagnostics	Profilers, Logs	Identify bottlenecks

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💡Summary (Short Answer)

"In ASP.NET Core, I improve performance using multi-level caching (in-memory, distributed, and output), async programming, optimized EF Core queries, response compression, and CDN-based static content delivery. I also use IHttpClientFactory for efficient HTTP calls, limit middleware overhead, and profile apps with Application Insights or AWS X-Ray to find hot spots. In cloud deployments, I leverage autoscaling and caching via AWS ElastiCache and CloudFront."