I'm semi-worried because I should be getting up in a few hours, but the spell of the espresso beans clearly has not lifted...so i'll keep going. :) Within the last few months, work has wrapped up on our "Processor Groups" project, otherwise known as Multi-Level CMT scheduling optimizations. The putback introduced (among other things) a platform independent abstraction for representing a group of logical CPUs with some physical or characteristic sharing relationship. As of Nevada build 57 (and Solaris 10 update 4), Solaris uses this abstraction to construct groupings of CPUs that have performance relevant hardware sharing relationships, including shared caches, pipelines, pipes to memory, etc. The kernel scheduler/dispatcher then implements load balancing and affinity policy against these groupings in an attempt to maximize throughput and improve cache utilization efficiency.

This infrastructural upgrade has replaced the kernel's legacy CMT scheduling framework (implemented in chip.c/chip.h), which provided for only a single level of optimization (physical processor). The PG infrastructure enables Solaris to optimize for N levels, which is needed in cases where multiple levels/types of hardware sharing exists between logical CPUs in the system. Longer term, we're interested in providing a PG based implementation for the scheduling side of the kernel's NUMA optimizations. In addition to simplifying the implementation, this would potentially get us to the point of a having an affinity/load balancing policy implementation that spans both NUMA and CMT.

The road ahead is an exciting one

Over the next year or two, i'll be focusing my efforts on Solaris platform independent power management policy...which will entail bringing (or coordinating to bring) power management awareness to the platform independent kernel subsystems that deal with power manageable resources. We'll start with the dispatcher. :)

"Tesla" is the code name for the project, which will be run "in the open" via OpenSolaris. Over the last week, i've been working on the logistical aspects of the project (getting content on the page, setting up mail aliases, figuring out the Mercurial SCM, etc.). I'm hoping the project will go live either tomorrow (uh, today) or Tuesday.

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