Real Case: Random apps running 100% CPU (advanced)

This is another 100% CPU issue.  This time I’m not working on any customer case as the issue is happening on my own Windows XP SP2 machine.  So I resolved trying to troubleshoot that just for fun J. First, let me explain the scenario: Random interactive applications, like Outlook, Word, Excel, Explorer, Internet Explorer etc,…

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Real Case: IIS and Asp.Net hanging or poor performance (intermediary)

This week I’m working on this case related to IIS6 server hosting an Asp.Net application (it’s a C# app) whose the performance is poor even when a very low number of users is hitting it.  The architecture is the classical web layer accessing the backend DB servers and my goal is to isolate the problem, i.e pinpoint where…

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/3GB, /PAE, AWE what??? (basic)

I’ve been following the discussions about these options for a long time. When it seems that everybody agrees on something, somebody else comes with a different understanding and the discussion starts all over again… The questions at the beginning of each thread about this subject are often the same: When should I use /3GB option,…

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Troubleshooting IIS 100% CPU issues – Step by Step (intermediary)

Processes consuming 100% of a system’s CPU time is such a situation everybody has faced at least once (likely much more than once :)), and normally as solution we just “kill the murderer” by stopping the culprit process.  But what was really causing that process to behave like that?  If you can’t properly answer this question you might…

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A new phase…

Even though this has been a strictly technical channel (I’ve never posted about anything else other than technical stuff) I know a lot of friends read it and so I decided to open an exception on this post and use it to publish something about me that also has a direct effect on how often and what type of content I will be able to keep…

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Kernel dump analysis – Bugcheck 1E (KMODE_EXCEPTION_NOT_HANDLED)

It’s been a long time since my last post, but for some reason lately I’ve been receiving so many nice feedbacks about the blog and the other posts that I feel really motivated again to post a new article.  See how important your feedback is for me? J Ok, normally I post about user mode…

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Tip: How many users are hitting my web site?

This is a question we hear very often from our customers, in forums or through distribution lists.  The reason we keep hearing the same question over the time is very simple:  There isn’t a definitive answer for that – At least not for IIS since it’s not exactly driven by the number of users hitting…

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Perfmon’s counters output format (tip)

The System Monitor (Perfmon.exe) reports the data gathered through some of its objects and counters with no formatting and depending on what kind of counters are you looking at, or how tired you are, sometimes this can be confusing and even cause misinterpretation problems. As an example, take the counter Processes::Virtual Bytes.  We normally have MBytes or…

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Kernel dump analysis – Bugcheck 0xA (IRQL_NOT_LESS_OR_EQUAL)

Yet another kernel memory dump to be analyzed – The bugcheck this time is the 0xA – IRQL_NOT_LESS_OR_EQUAL.   To better understand what this message means we would need a little background on Windows Internals but basically when executing anything at a interrupt request level (IRQL) = 2 or higher (in normal circumstances instructions get executed at…

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How to identify the process and thread being called in a COM call from a thread stack

I’ve just published a post on how to manually identify which classic ASP page is being processed by a specific thread.  Following the same idea you can also identify COM calls being made by a thread.   As always, first identify the thread doing the COM call you want investigate and then look at the thread…

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