C# Driver: High CPU time spent in IFindFluentExtensions.SingleOrDefaultAsync

Working with Data Drivers
1

Hi,

When performing load tests for our API calling MongoDB via (newest) .NET driver we observed high CPU spikes for e.g. 100 concurrent users.

11th Gen Intel(R) Core™ i7-11850H @ 2.50GHz 2.50 GHz

Spikes are up to 80-90%.

In Visual Studio CPU profiling lists the top congestion in

Function Name Total CPU [unit, %] Self CPU [unit, %] Module

  • [External Call]
    MongoDB.Driver.IFindFluentExtensions.SingleOrDefaultAsync<T1, T2>(MongoDB.Driver.IFindFluent<T1, T2>, System.Threading.CancellationToken) 262580 (29.37%) 262541 (29.36%) mongodb.driver

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Can you explain what may be reason behind. We have experimented with limiting projection size but still CPU reaches high levels.

Is there any active waiting being performed?

Thanks!