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Re: asymmetric smp

On 2014-04-01 01:47, Erik Fair wrote:

On Mar 27, 2014, at 11:29 , matthew green <> wrote:

it certainly can be improved for this situation, but i've
got an SS10 with mis-matched cpus (2x100mhz, 1x150mhz,
the latter with a bigger cache and thus significantly
faster than the other cpus) and it works pretty fine.

so - my guess is that some of the power and performance
issues will still need work, but the system will boot
and run normally without special work.

I believe the point is to more nearly optimally schedule processes according to 
their needs on the processor(s) whose characteristics better match. Mr. Thomas 
also noted that this has energy use (power budget) implications.

Apple started a push in the "energy efficient software" direction last year at WWDC, 
clearly to prod third-party software developers into ligher impact on the energy budgets of both 
iOS mobile devices and MacOS X based laptops, but this sort of thing also has implications for HVAC 
and power bills in large scale data centers too. As I have been wont to say for a decade or two, 
"the hardware giveth and the software taketh away" and it would be a good thing for 
NetBSD's ongoing relevance if we paid some attention to efficiency of our software's algorithms and 
execution efficiency with the explicit goal of minimizing energy use of the computers our system 
runs on.

There are limits to what we can do; if users choose to run inefficient 
applications, or combine the software we provide in less-than-optimal ways with 
shell scripts, that's on them - we've (hopefully) done all we can do to provide 
them with the best tools.

Good points.
Is this the right time to ask why booting NetBSD on a VAX (a 3500) now takes more than 15 minutes? What is the system doing all that time???


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