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From: Robert Watson <rwatson@FreeBSD.org>
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To: Warner Losh <imp@FreeBSD.org>
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Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/arm/conf NSLU
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On Mon, 8 Sep 2008, Warner Losh wrote:

>  Commit the no-brainer parts of my space saving kernel experiments.  We
>  don't inline the locking primitives, and only grab those parts of mii
>  that we really need.  Other space optimizations are too agressive for
>  the generic file (removing all of usb, and loading it as kernel
>  modules).

It's been a few years since we selected defaults on lock inlining (and other 
optional parameters), and it might well be time to re-evaluate our defaults. 
Cache footprint on code continues to play a significant role in performance, 
the trade-offs for function invocation have changed quite a bit over the 
years.  A more thorough performance analysis of lock inlining is probably 
overdue for all platforms, not just small embedded ones.

Robert N M Watson
Computer Laboratory
University of Cambridge