Two cool debugger tips that I learnt today

Tue, July 29, 2008, 08:21 PM under dotNET
Tip #1 – datatips on comments
One of the coolest debugger features introduced in VS2005 was DataTips (grey editable, navigable tooltips on steroids that also become transparent when you hold down the Ctrl key). Did you know that you can get data tips for commented code? At first this made me raise an eyebrow, but I can see how for some piece of code I may always need to inspect some other variables quickly and do not want to have to enter them in the watch window manually or navigate to the required area from existing variables that do exist in code. Here is a screenshot that shows this feature in action:

Notice how the datatip appears after highlighting a variable that is in a commented area of the editor (my highlight is set to yellow).

Tip #2 – save output window
In Visual Studio many times we need to transfer the text from the Output window to an actual txt file. Dunno about you, but I always selected all (Ctrl+A), copied (Ctrl+C) and then pasted (Ctrl+V) into a notepad instance that I always have running (Alt+TAB). It turns out that there is a direct way of saving that output to a file. Simply hit Ctrl+S (or invoke it from the menu item) once you've given focus to the Output window – nice!

What cool debugger features do you like in Visual Studio (or would like to see)?

Moore's Law in relation to manycore

Mon, July 28, 2008, 01:40 AM under ParallelComputing
When most people's brains first light up on why parallelism is the next BigThing, some jump to the conclusion that Moore's law is over. Let's clear that up below.

All of you know Gordon Moore's law which boils down to the prediction of
"the number of transistors on a chip will double about every two years"
In the last 30-40 years the previous prediction has manifested itself in clock speed increases and that is what has tricked most of us to associate Moore's law with CPU speed.

So, now that chip manufacturers cannot make single CPUs any faster (well, they can, but they can't cool them down enough to make them useful), they are resorting to having chips with multiple cores, which we are terming the manycore shift. The manycore shift has a profound impact on developers (especially those programming for the desktop client) in that their software now has to learn how to take advantage of parallelism.

So if you followed the logical flow so far, you'll conclude that Moore's law is still alive: we are still getting more silicon, but it does not translate to increased linear speed, but rather to parallel "engines" that your software must learn to utilise.

I am glad we cleared that up :)

Name Your Threads

Tue, July 22, 2008, 02:15 AM under ParallelComputing
One of my pet peeves is ensuring that whenever there is code that explicitly creates a thread, to always have an accompanying statement that names the thread. This is invaluable in debugging. With managed code, it is so simple, just one extra statement to set the thread's Name property (which you can only do once at runtime, of course).

This is such a useful thing to have when debugging, that in VS2008 the ability was added to name threads after execution had started. The idea there is for naming Threads that you don't control but still need to easily identify for debugging purposes. The name does not persist cross debugging sessions and indeed it is not used at runtime by anything other than your... eyes. I describe this feature as part of my video on all the new VS2008 threading enhancements (watch minutes 06:00 through 08:20, although I recommend the full 15 minutes).

At the OS level the ability to have names against threads is not supported (but you can use nice HEX ids to assist with your debugging ;)). Recently I discovered that there is an old trick (or hack IMO) that you can use with certain tools (inc. Visual Studio) to set names on native threads too. To get the details visit this short How To on MSDN. I did a quick search and discovered two more places on the web where this is described. One is on codeproject which is blatantly lifted from MSDN but it adds a couple of screenshots. The other also points to (an obsolete place on) MSDN and adds a bit more detail.

In short, for my managed friends: Search your code base now for the string "= new Thread" and for every match that you find, verify that you are also setting the Name property. You'll thank me later.

Quotes about concurrency by AndersH

Sat, July 12, 2008, 08:14 PM under ParallelComputing
Yesterday a new 1-hour video interview on C# 4.0 was posted on channel9.

At some point the question is posed to Anders:
"What are some of the big issues that you are thinking about for the future?"
and Anders' reply (ffw to 39:56) identifies concurrency as the #1 thing:
"Concurrency is by far... profoundly changing... Moore's law... we've been ignoring concurrency because we could... now we can't... it is a damn hard problem..."
My favorite quote comes at 45:13 and includes hand gestures too:
"It is foolish to think that somehow we are going to be able to pepper concurrency on your code and you wouldn't need to modify anything in your apps today for them to run concurrently"
For the stuff in-between and to get the complete picture, watch the video.


Wed, July 2, 2008, 08:56 PM under Personal
As I did last year, thought I'd share that today (or yesterday depending on where you are) is(was) my 34th. I'll always remember this day as the day I received my SSN (progressing nicely thru the unordered list).