Re: HEADS UP: new NSS

On Thu, 17 Apr 2003, Dan Nelson wrote:

> > If switching to a fully dynamically linked system is desired before
> > 6.0 then it needs to happen before 5.2.  I'm not opposed to this.
> 
> I'm more worried about the performance hit than foot-shooting (schg is
> protection enough I think, and I like beagles). 
> 
> I believe dynamically-linked programs still are ~20% slower than static
> ones, and for small programs like sed, awk, expr, sh, basename, tr, and
> the like, the larger (constant) startup time becomes significant also. 
> 
> Anyone want to benchmark a medium-sized portbuild with static vs dynamic
> /bin and /sbin? 

Well, I think that the measurements should be done, but it's worth noting
that several of the programs you quote above have been dynamically linked
for years:

sed		dynamic
awk		dynamic
expr		static
sh		static
basename	dynamic
tr		dynamic

Some might argue that even to support NSS, expr wouldn't need to become
dynamic. 

One of the noted benefits of running with a dynamic system is that you can
actually save a fair amount of memory by not requiring separate physical
memory storage for each instance of libc.  There are a number of
trade-offs, and we're certainly not the first to approach this decision
:-).  I'd be very interested in seeing some micro-benchmark and
macro-benchmark performance results, however.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert_at_fledge.watson.org      Network Associates Laboratories