When we have to debug applications that use concurrency, perhaps written in Java, all we get from the debugger is a list of threads, perhaps some information about held locks, and the ability to step through each thread separately.
[Disclaimer: I am one of the assistants supporting the RACES’12 organizers and a PC member.]
You got a big multicore, or manycore machine, but do not have a clue of how to actually use it, because your application doesn’t seem to scale naturally? Well, that seems to be a problem many people are facing in our new manycore age. One possible solution might be to accept less precise answers by relaxing synchronization constraints. That could allow us to circumvent Amdahl’s law when Gustafson is out of reach.
The second day of the technical tracks started with a keynote by Markus Püschel. He is not the typical programming language researcher you meet at OOPSLA, but he does research in automatic optimization of programs. In his keynote, he showed a number of examples how to get the best performance for a given algorithm out of a particular processor architecture. Today’s compilers are still not up to the task, and will probably never be up to it. Given a naïve implementation, hand-optimized C code can have 10x speedup when dependencies are made explicit, and the compiler knows that no aliasing can happen. He was then discussing how that can be approached in an automated way, and was also thinking about what programming languages could do.
The first day of the technical tracks including OOPSLA started with a keynote by Ivan Sutherland titled The Sequential Prison. His main point was that the way we think and the way we build machines and software is based on sequential concepts. The words we use to communicate and express ourselves are often of a very sequential nature. His examples included: call, do, repeat, program, and instruction. Other examples that shape and restrict our way of thinking are for instance basic data structures and concepts like strings (character sequences). However, we also use words that enable thinking about concurrency and parallelism much better. His examples for these included: configure, pipeline, connect, channel, network, and path.
The second conference day was unfortunately full of “conflicts of interest”… It was pretty hard to choose between all the talks on the schedule.
And here we go again: SPLASH 2011 has started with its first day of workshops.
As usual I will write about a few of my personal highlights of SPLASH and the co-located workshops. That is mostly from my spotty notes, and from memory, so I don’t guarantee 100% accuracy, especially with respect to what other people might have said.
In October, I will give a brief presentation on the state of affairs with my PhD research at the SPLASH 2010 Doctoral Symposium. The basic idea has not changed since my last presentation at the TiC’10 summer school. I haven’t been able to do a lot of real work for it, but the ideas are a bit clearer now. The following two-page proposal will be published as part of the conference proceedings.