Multiple Threads

The following abstracts were submitted for Sun’s internal Customer Engineering Conference 2006. Of course there is no guarantee that this material will be accepted by the CEC panel, but I’d be happy to present the same (or similar) material at other events. If you’re interested, please drop me a line.

Microbenchmarking – Friend or Foe?

Many purchasing, configuration and development choices are made
on the basis of benchmark data. Industry organisations such as
SPEC and TPC exist to inject a measure of realism and fairness
into the exercise. However, such benchmarks are not for the faint
hearted (e.g. they require considerable hardware, software and
people resources). Additionally, the customer may feel that an
industry-standard benchmark is not sufficiently close to their
own perceived requirements. Yet building a bespoke benchmark for
a real world application workload is an order of magnitude harder
than going with something “off the peg”. It is at this point that
an alarming number of customers make the irrational leap to some
form of microbenchmarking — whether it is good old “dd” to test
an I/O subsystem, or perhaps LMbench’s notion of “context switch
latency”. The whole is rarely greater than the sum of its parts,
but the issue often ignored is that a microbenchmark — by very
definition — only considers one tiny component at a time, and
then only covers a small subset of functionality in total.
Furthermore, it is often observed that some microbenchmarks are
very poor predictors of actual system performance under real
world workloads.

Is there any place for microbenchmarking? Certainly, we need to
be aware that customers may be conducting ill-advised tests
behind closed doors. But should we ever dare engage in such
dubious activities ourselves? In short: yes! In the right hands
microbenchmarks can highlight components likely to respond well
to tuning, and assist in the tuning process itself. This session
will focus on libMicro: an in-house, extensible, portable suite
of microbenchmarks first used to drive performance improvements in
Solaris 10. The libMicro project was driven by the conviction that
“If Linux is faster, it’s a Solaris bug”. However, some of the
initial data made the case so strongly that we chose to adopt
the Monsters Inc. slogan “We scare because we care” at first!
libMicro is now available to you and your customers under the
CDDL via the OpenSolaris programme. Key components of libMicro
will be demonstrated during this session. The demo will include
data collection, reporting and adding of new cases to the suite.

Note: I was taking them seriously about 2500 chars and two paragraphs.

Synchronicity: Solaris Threads and CoolThreads

The Unified Process Model is one of the best kept secrets in Solaris 10. Yet this “so what?” feature entailed changes to over 1600 source files. But was it all a waste of effort? For over a decade Sun has been recognised as a thought leader in software multithreading, but did we lose the plot when we dropped the idealistic two level MxN implementation for something much simpler in Solaris 9?

To both of these questions we must answer a resounding “No!”. Indeed, the Unified Process Model, under which every process is now potentially a multithreaded process, was only possible by a simpler, more scalable, more reliable, more maintainable, realistic one level 1:1 implementation. And all this goodness just happens to coincide with the CoolThreads revolution. As other vendors chime in with CMT, Solaris is streets ahead of Linux and other platforms in being able to deliver real benefits from this technology. It is extremely important that we are able to understand, articulate and exploit this synchronicity.

Note: this time I realised that they didn’t really mean 2500 chars!

DTrace for Dummies

Wonder what all the fuss is about? Need a good reason before you engage
your brain with this stuff? Think this may be one new trick too far
for an aging dog? Just curious? Then this session is for you! We have
a reputation for making DTrace come alive for even the most skeptical
and indifferent of crowds — D is certainly not for “dull” at our shows!
Don’t worry, we won’t get you bogged down in syntax or architecture.
But we will convince you of the dynamite that is the DTrace observability
revolution — that, or you are dummer that we thought! Everything you
see will happen live. We don’t use any canned scripts. Anything could
happen. You’d be a fool to miss it!

Notes: This was a joint submisson from me and Jon Haslam.
We’ve found our combination of sound technical content and brit humour
very effective at getting across the DTrace value proposition to a wide
audience. We first did our double act (Jon types while Phil talks) at
SUPerG 2004. Following rave reviews we were asked to present a plenary
session at SUPerG 2005.

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