ASP.NET Core 2.2 experiencing high CPU usage

1
votes

So I have hosted asp.net core 2.2 web service on Azure(S2 plan). The problem is that my application sometimes getting high CPU usage(almost 99%). What I have done for now - checked process explorer on azure. I see there a lot of processes who are consuming CPU. Maybe someone knows if it's okay for these processes consume CPU? Currently, I don't have an idea where do they come from. Maybe it's normal to have them here.

Shortly about my application: Currently, there is not much traffic. 500-600 request in a day. Most of the request is used to communicate with MS SQL by querying records, adding, etc. As well I am using MS Websocket, but high CPU happens when no WebSocket client is connected to web service, so I hardly believe that it's a cause. I tried to use apache ab for load testing, but there isn't any pattern, that after one request's load test, I would get high CPU. So sometimes happens, sometimes don't during load testing.

So I just update screenshot of processes, I see that lots of threads are being locked/used during the time when fluent migrator start running its logging.

Update* I will remove fluent migrator logging middleware from Configure method. Will look forward with the situation. enter image description here

UPDATE**

So I removed logging of FluentMigrator. Until now I didn't notice any CPU usage over 90%.

But still, I am confused. My CPU usage is spinning. Is it health CPU usage graph or not? Also, I tried to make a load test on the websocket server. I made a script that calls some functions of WebSocket every 100ms from 6-7 clients. So every 100ms there are 7 calls to WebSocket server from different clients, every function within itself queries some data/insert (approximately 3-4 queries of every WebSocket function).

What I did notice, on Azure S1 DTU 20 after 2min I am getting out of SQL pool connections, If I increase DTU to 100, it handles 7 clients properly without any errors of 'no connection pool'. So the first question: is it a normal CPU spinning? Second: should I get an error message of 'no SQL connection free' using this kind of load test on DTU 10 Azure SQL. I am afraid that when creating a scoped service on singleton WebSocket Service I am leaking connections. This topic gets too long, maybe I should move it to a new topic? enter image description here

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1
azureasp.net-corecpu-usageprocess-explorer
It would help if you would add more context. What precisely does your application, how big it is, how much traffic it handles, whether it is simple MVC app or some API running complex image processing. – Prolog
In a few minutes, I will update – Andrius
"(...) high CPU happens when no WebSocket client is connected to web service" - are you running any background jobs? In other words - should the application do nothing when it recieves no requests? – Prolog
There are background services using hangfire, but I have disabled them for testing purposes and they did not affect CPU usage as well. – Andrius
Well, CPU now is 97%. There are lots of task function running on, but they come not from request but probably from fluent migrator logging services – Andrius

1 Answers

3
votes

At this stage I would say you need to profile your application and figure out what areas of your code are CPU intensive. In the past I have used dotTrace, this highlighted methods which are the most expensive with a call tree.

Once you know what areas of your code base are the least efficient, you can begin to refactor them so that they are more efficient. This could simply be changing some small operations, adding caching for queries or using distributed locking for example.

I believe the reason the other DLLs are showing CPU usage is because your code calling methods which are within those DLLs.