Are you GLAD?

Holidays are almost upon us. Last year around Christmas time I wrote a set of GC ETW blog entries to help with diagnosing GC heap related issues. This year I want to discuss taking that a (big) step further and making an SDK that does the analysis for you using these ETW events – so…


Allocating on the stack or the heap?

A recent discussion prompted me to write this blog entry. The question there was “when should I allocate something on the stack vs on the heap?”. I searched around and there are plenty of articles that talk about *what* gets allocated on the stack vs on the heap, but not how you should decide what…


GC ETW Events – 3

In the last blog entry we looked at a particular GC trigger reason – InducedNotForced GCs. There are 2 other triggered reasons for induced GCs are: InducedLowMemory – GC subscribes to the low memory notification from the OS and when the OS notifies us that “the memory is low on the machine” a GC is…


GC ETW events – 2

Before we continue from where we left off in the last blog entry I wanted to give a performance tip on managed memory analysis. As some of you who have already tried out Perfview you probably noticed it has a Heap Snapshot feature (in the PerfView UI, if you click on Memory\Take Heap Snapshot) which…


GC ETW events – 1

A lot of people have mentioned to me that I have not posted anything for a long time. I do realize it and do appreciate being asked to write more. Well, it’s end of year and I am starting vacation so I thought I’d write something light that perhaps makes good reading around Christmas time…


So, what’s new in the CLR 4.0 GC?

PDC 2008 happened not long ago so I get to write another “what’s new in GC” blog entry. For quite a while now I’ve been working on a new concurrent GC that replaces the existing one. And this new concurrent GC is called “background GC”. First of all let me apologize for having not written…


64-bit vs 32-bit

As 64-bit machines become more common, the problems we need to solve also evolve. In this post I’d like to talk about what it means for the GC and the applications’ memory usage when we move from 32-bit to 64-bit.   One big limitation of 32-bit is the virtual memory address space – as a…


Difference Between Perf Data Reported by Different Tools – 4

.NET CLR Memory\% Time in GC counter and !runaway on thread(s) doing GC. The 2 common ways people use to look at the time spent in GC are the % Time in GC performance counter under .NET CLR Memory, and the CPU time displayed by the !runaway debugger command in cdb/windbg. What do they mean…


Difference Between Perf Data Reported by Different Tools – 3

Both the !SOS.gchandles command (added in CLR 2.0) and the .NET CLR Memory\# GC Handles counter show you the number of GC handles you have in your process. The # GC Handles counter is one of the rare counters in the .NET CLR Memory category that doesn’t get updated at the end of each GC….


Difference Between Perf Data Reported by Different Tools – 1

So, there are many perf tools and some of them report either the same or the same type of data. I want to talk about various differences between the ones related to managed heap investigation. This is not supposed to cover everything..just the ones I think people use frequently. Managed Heap Size We have both…