I would like to check on the specifications due to an IIS version upgrade.

umz 0

When we updated our ASP web app from IIS 8.0 to IIS 10.0, the following event occurred.
CPU usage reaches 100% when using the web app, and the usage remains at 100% until W3wp.exe is taskkilled in the task manager

Since we cannot determine the cause, we are thinking of trying the following from Microsft's troubleshooting
https://learn.microsoft.com/ja-jp/troubleshoot/developer/webapps/iis/health-diagnostic-performance/troubleshoot-high-cpu-in-iis- app-pool

The web server is built in a production environment and a test environment, and since this issue does not occur in the test environment, we are planning to investigate by putting the troubleshooting tool in the production environment.
Should we not do this in the production environment where the service is running?

Translated with DeepL

Yurong Dai-MSFT 2,781 Reputation points Microsoft Vendor

2023-10-16T02:35:01.37+00:00

Hi @梅沢　隆史,

When a server hangs, crashes, or suffers from low CPU performance, you can use PerfMon to collect data and DebugDiag for analysis. But analyzing the dump file is a complex process, so I recommend you to open a support ticket via: https://support.microsoft.com, there will be professional technicians to assist you in grabbing the dump file and analyzing it.
umz 0 Reputation points

2023-10-18T01:56:39.91+00:00

返信が遅く、申し訳ございません。回答ありがとうございます。

ご提案いただいた、ツールを使って調査してみようと思います。

本番環境での実行にあたり、性能面での影響が懸念されるため、テスト環境で十分に確認した上で調査をしていこうと思います。

1 answer

MotoX80 31,651 Reputation points

2023-10-14T23:45:38.7366667+00:00

Is it pure ASP or .Net (ASPX)?

Have you been able to identify a page that is causing the problem?

On the server tab, click on Worker Processes, and then right click on the app pool. Select view current requests.

It would look something like this. Is anything running when the cpu hits 100? Monitor your site during the day and see if you have requests that never end.

Are you seeing any errors in the IIS logs or the HTTPERR logs (C:\Windows\System32\LogFiles\HTTPERR)?

Next I would use Process Monitor to see if w3wp.exe is in a pure loop or if it is trying to access some file or registry entry. Set a filter for "process name is w3wp.exe".

https://learn.microsoft.com/en-us/sysinternals/downloads/procmon
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umz 0 Reputation points

2023-10-18T02:02:06.55+00:00

Sorry for the late reply. Thank you for your answer.

The application is .Net (ASPX).

Have you been able to identify the page(s) causing the problem?

We have narrowed it down to some extent, but have not been able to identify it.

Thank you for even describing how to check the process.

We will refer to this when we investigate the cause of the problem using Process Monitor.

umz 0 Reputation points

2023-10-18T02:10:17.61+00:00

返信が遅く、申し訳ございません。回答ありがとうございます。

アプリケーションは、.Net (ASPX)です。

対象の範囲はある程度絞れてきましたが、問題の原因となっているページは特定できておりません。

また、IISのログには、エラーは出力されておりませんでした。

プロセスモニターの確認方法までありがとうございます。

プロセスモニターで確認するときに参考にさせていただきます。

MotoX80 31,651 Reputation points

2023-10-18T14:56:00.36+00:00

You do not need to install DebugDiag on your production server. You can install it on a test server or workstation and then use task manager on your production server to create a memory dump of your w3wp.exe process. Copy that file to the test server and run the analysis there.

That will produce a very (VERY!) detailed analysis of the process and if you have never looked at that before it will be a challenge for you to interpret the results. As @Yurong Dai-MSFT noted, you might be better off to create a support case and let the IIS/,Net experts analyze the dump.

I would also suggest using perfmon on your server and monitor .Net and IIS counters and monitor memory usage over time.

https://techcommunity.microsoft.com/t5/iis-support-blog/perfmon-for-iis-and-asp-net/ba-p/826721
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