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Date: Tue, 31 Mar 2015 21:50:48 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Bruce Evans <brde@optusnet.com.au>
Subject: Re: svn commit: r280279 - head/sys/sys
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On Tue, Mar 31, 2015 at 03:49:28PM +1100, Bruce Evans wrote:
> It looks a bit overengineered to me.  A bit like my function pointers
> for the bcopy() family on i386.  bcopy() is a bulk operation, so in
> theory you can do it much faster by selecting the best available
> version at runtime.  In practice, the gains were not large and are
> too machine-dependent to maintain.  It is even harder to get large
> gains and maintain them by selecting individual instructions at runtime.
> 
Yes, it is similar to bcopy.  The difference in motivation is that the
IFUNCs are for features, not for speed.  The existing patch already
demostrates this WRT self-snoop and different methods of saving FPU
state.