October 27, 2015
I travel to a lot of conferences, but among the ones I like the most are Software Architect and DevWeek. I'm writing this post on the flight back home from Software Architect, where I had the pleasure of delivering a workshop and three talks. If you attended the conference, thanks a lot for coming and I hope you find the materials useful; if you haven't been to the conference, I expect to see you next year!
My first talk was an introduction to Haskell for developers with no prior experience in functional programming. For me personally, Haskell is not...
October 23, 2015
The Windows heap manager was designed to avoid the overhead of having to allocate virtual memory directly with VirtualAlloc, among other things. If you only need a 20-byte object, it's a waste to call a system service (involving a user-kernel transition) and allocate a full page. The heap manager avoids that overhead by managing large blocks of virtual memory in user mode---it is implemented in ntdll.dll.
However, when you allocate particularly large blocks of memory (>= 512KB at the time of writing), the heap manager doesn't see a reason to interfere, so it just forwards your request to VirtualAlloc. It still knows about...
October 22, 2015
This is my second TechDays this year--I've had the pleasure of visiting the Netherlands and now also Sweden to speak at TechDays on a variety of topics. Both events had quite a special atmosphere with a lot of activity, a lot more session slots than usual at software conferences, and a great selection of international speakers (except for your humble servant, of course). Even though most talks were in languages I don't understand, I really enjoyed my time.
But I'm guessing you're here because you want to put your hands on materials from my two talks--so here they are, without...
September 30, 2015
In my previous post on MiniDumper, I promised to explain in more detail how it figures out which memory ranges are required for .NET heap analysis. This is an interesting story, actually, because I tried a couple of approaches that failed before coming up with the final idea. Basically, I knew that a dump with full memory contains way more information than is necessary for .NET dump analysis. Even if you need the entire .NET heap available, you typically don't need a bunch of other memory ranges: executable code, Win32 heaps, unused regions of thread stacks, and so much more.
August 31, 2015
Oops! This was sitting in my queue for several months now, and I just noticed it needs to be published. But better late than never I guess. Here goes:
I've been lucky enough to be invited to speak at TechDays Netherlands again this year. This time I was asked to do four talks on some of my favorite subjects -- performance optimization, debugging, and diagnostics. Same as last year, the conference was impeccably organized.
I'm really looking forward to next year's TechDays :-) In the meantime, here are the materials from my talks.
Making .NET Applications Faster
My usual favorite on improving...
August 19, 2015
MiniDumper is born. It is an open source library and command-line tool that can generate dump files of .NET processes. However, unlike standard tools such as Procdump, MiniDumper has three modes of operation:
Full memory dumps (analogous to Procdump's -ma option). This is a complete dump of the process' memory, which includes the CLR heap but also a bunch of unnecessary information if you're mostly working with .NET applications. For example, a full memory dump will contain the binary code for all loaded modules, the unmanaged heap data, and a lot more.
Heap-only dumps (no Procdump analog). This is a dump that contains the...
August 18, 2015
I know, I'm working hard on beating my record for longest post title ever. I also thought of adding a random Win32 API to the title, say CoMarshalInterThreadInterfaceInStream or AccessCheckByTypeResultListAndAuditAlarmByHandle. But I didn't, so here we are. What was I saying? Oh yeah, a neat stack corruption I spent a couple of hours chasing last week.
I was doing my usual reverse P/Invoke where I call a Windows API and pass a delegate as a callback. There's a bunch of APIs in Win32 that take callbacks, but for the sake of this post let's take a look at a very simple example...
August 15, 2015
The C++ language many of us are using today goes back more than thirty years. You might be using some “newer” features, such as templates or the standard library, which have been standardized around 1998 – the previous millennium. Since 1998, C++ has seen two major international standards – C++ 11 and C++ 14, and work is in progress on another major revision to be published in 2017.
Over the last few years, C++ developers all over the world are transitioning to the new, modern C++. It’s not just a matter of language features or library APIs. It’s a matter...
July 30, 2015
tl;dr -- when migrating from Visual C++ 2013 to Visual C++ 2015, make sure that (1) your destructors do not throw exceptions, and (2) your move constructors are marked noexcept if they do not throw exceptions.
Less than a year ago, I described some of the reasons why noexcept is an important C++ language feature that lurks in the background and waits for the right moment to bite you in the neck.
Specifically, destructors and move constructors should ideally be marked as noexcept. For move constructors, this "ideally" means there are corner cases where performance won't be optimal if you don't mark the move constructor noexcept; for destructors,...
July 16, 2015
It was my first time at NDC Oslo, and my first time in Norway as well. I was really impressed with the city of Oslo, with the conference venue, with the energy that could be felt all around the halls and expos, and with the great hospitality of the conference organizers.
I'm really looking forward to be back at NDC London or NDC Oslo (and who knows, maybe NDC Australia too?). In the meantime, here are the materials from my two talks, both of which were recorded and are already available online to watch.
Swift: Apple's New Programming Language for iOS and...