Tag Archives: scalability

Better Parallelization And Scalability

Obviously, I have more than enough FATE-related work to keep my free time filled for the foreseeable future. But that doesn’t stop me from coming up with more ideas for completely revising the underlying architecture. And it’s always good to hash these ideas out on this blog since it: 1) helps me clarify the issues; 2) allows other people to jump in with improvements and alternatives; 3) allows me to put as much thought into these ideas as possible. Let’s face it– whatever design decisions I make for FATE are the ones the team tends to be stuck with for a long time.

Parallel FATE

People who dig into FATE and the various commands it executes in order to build and test FFmpeg often ask why I only perform singly-threaded builds, i.e., why not build with ‘make -j2’ on a dual-core machine? It would be faster, right? Well, yes, but only for the build phase. The test phase (which usually takes longer) is still highly serial (though the ‘make test’ regression suite can also be parallelized). A pragmatic reason I have for not wanting to multi-thread the build is that the stdout/stderr text lines can easily get jumbled which makes it more difficult to diagnose failures.

I do, however, put both cores on the main dual-core FATE machine to use– I run 2 separate installations of the FATE script, thus divvying the labor by having each core handle roughly half of the configurations. Thus far, one installation runs the x86_64 configs while the other installation is a 32-bit chroot environment running the x86_32 configs.

Can I come up with a better parallelization system? I think I might be able to. And to what end? Taking this whole operation to the next level, where “next level” is defined loosely as getting a few hundred more tests into the database while perhaps upgrading to a faster machine with more than 2 cores which is responsible for more than just native machine builds. Also, I am experimenting with moving the PowerPC builds to a faster (x86) machine for building. Better support for cross compiling and remote testing is driving some of this refactoring.

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