This is my first entry, and what better way to start, than with a great event. Last week here at Sao Paulo occurred a tree day workshop that had as subject openSPARC specification and FPGA implementation. The workshop happened from 24 through 26 March and was hosted by the Grupo de Sistemas Pervasivos e de Alto Desempenho (Pervasive systems and high performance group - PAD) of the Laboratory of Integrated Systems (LSI) of the Polytechnic School of the University of São Paulo (EPUSP). This was the first of many events related to the openSPARC center of excellence program at USP.

The compiler flag -fast gets an unfair rap. Even the compiler reports:

cc: Warning: -xarch=native has been explicitly specified, or 



implicitly specified by a macro option, -xarch=native on this 



architecture implies -xarch=sparcvis2 which generates code that 



does not run on pre UltraSPARC III processors

which is hardly fair given the the UltraSPARC III line came out about 8 years ago! So I want to quickly discuss what's good about the option, and what reasons there are to be cautious.

Dan Berger posted a comment about the compiler flags we'd used for Ruby. Basically, we've not done compiler flag tuning yet, so I'll write a quick outline of the first steps in tuning an application.

Ubuntu is on the upswing. The signs are everywhere (including here with its tie-up with IBM). Canonical, which developed this version of Linux, has been very busy talking with the major server and desktop vendors and is making inroads with both.

I've been invited to appear in Sun's "Meet the authors" programme in Second Life. I'll be talking about my book on 24th April, 9am PST. Hopefully there will be copies of my free book available to some fortunate attendants.

Sun's Microelectronics Group has been busy over the past few months with announcements including a new foundry partnership with the Taiwan Semiconductor Manufacturer Co. and more recently announcing an OpenSPARC agreement with the China Ministry of Education catching the eyes and ears of industry watchers. 

As soon as KIWI enters the use cases stage, collaboration with business partners is going to gain particular importance. One of these partners is Sun Microsystems - who hardly need an introduction. Yet an interesting new fact that I learned about Sun on Thursday was that they are not only a main contributor to open source software development, but that they are also opensourcing hardware: OpenSPARC is the world’s first free 64-bit micro-processor - the source code for the OpenSPARC T2 chip was released unter GNU GPL and can be downloaded here.

One of the questions people ask is when to develop 64-bit apps vs 32-bit apps. The answer is not totally clear cut, it depends on the application and the platform. So here's my take on it.

The programming language Ruby is run on a VM. So the VM is responsible for context switches as well as garbage collection. Consequently, the code contains calls to flush register windows. A colleague of mine, Miriam Blatt, has been examining the code and we think we've found some places where the calls to flush register windows are unnecessary. The code appears in versions 1.8/1.9 of Ruby, but I'll focus on 1.8.* in this discussion.

The SPARC architecture has an interesting feature called Register Windows. The idea is that the processor should contain multiple sets of registers on chip. When a new routine is called, the processor can give a fresh set of registers to the new routine, preserving the value of the old registers. When the new routine completes and control returns to the calling routine, the register values for the old routine are also restored. The idea is for the chip not to have to save and load the values held in registers whenever a routine is called; this reduces memory traffic and should improve performance.