The Pit of Success

Pit of Success
: in stark contrast to a summit, a
peak, or a journey across a desert to find victory through many trials and
surprises, we want our customers to simply fall into winning practices by using
our platform and frameworks. To
the extent that we make it easy to get into trouble we fail.

-Rico Mariani, MS Research MindSwap Oct 2003.


I had a chance hear Rico Mariani do
his stump speech on performance of managed code to an audience of very senior
technical folks (not sure why they let me in)… As a performance architect on the CLR
team Rico has a ton of passion for how we can change internal CLR details to
make performance (more specifically workingset) better. He talked about some very cool things we
are doing in Whidbey around NGen, VTable layout etc for saving a few bytes per
type or instance. All very cool
stuff. And in fact we see some
fairly substantial performance wins in our performance test cases in the

But our experience with in house,
real world applications has been that they are not realizing this level of
performance win. Why? Turns out their performance is dominated
by other factors. The big wins we
realized at the CLR level are just noise compared to other performance problems
in the applications. With just a
few days of work our pref team was able to improve the performance of one of
these in house applications more significantly than all the CLR level
improvements combined. Their findings are
published here
. This is NOT because the app developers
are a bunch of clowns. Rather it is
because, as hard as we tried in V1, there were still some places where the
design of the platform leads them down the wrong path.

Because he was talking (mainly) to a
set of platform folks he admonished us to think about how we can build platforms
that lead developers to write great, high performance code such that developers
just fall into doing the “right thing”.
Rico called this the Pit of Success. That concept really resonated with
me. More generalized, it is the key
point of good API design. We should
build APIs that steer and point developers in the right direction. Types should be defined with a clear
contact that communicates effectively how they are to be used (and how not
to). I am not just talking about
the docs and samples (although those are good) but in the design of the
APIs. For example, give the
“pretty” name to the types most developers should use (ie. “Foo” and

A powerful thought, crystallized
well…. Enjoy.