about "optimize" files

Bruce Dubbs bruce.dubbs at gmail.com
Wed Nov 13 12:47:25 PST 2013

Pierre Labastie wrote:
> Hi all,
> I'd like to change the default optimizations we ship with jhalfs.
> First, the opt_override file
> The line:
> zlib    defOpt_fPIC
> is not needed anymore with recent (less than 4 year old at least)
> versions of zlib.
> I do not even know if setting -fPIC by hand does not defeat some
> automatic detection.
> Also, the line:
> glibc    noOpt
> is IMHO not needed: if somebody wants to use optimization, I would guess
> that glibc is a good start...
> Usually, modern versions of glibc accept very well optimization. If at
> some time, optimization becomes broken, I think it is up to the user to
> figure that out and to add the line in opt_override!

I agree.  The only problem is when we get messages saying that something 
doesn't work and they neglect to say that they know better than the 
glibc devs and change the optimization.

> for gcc, noOpt is needed, and for grub, I do not know, but it does not
> hurt...

It's kinda dumb to change optimization flags on GRUB.  The execution 
time is negligible and any size changes are not significant.

> Now, the opt_config file. I'd like to ship it with
> MAKFLAGS="-j5"
> (quadricore CPUs are very common these days)

I'd rather make that a selectable option with -j1 the default.

> and DEF_OPT_MODE=noOpt
> This is the most likely way people would want to use the file: job
> parallelization, but otherwise no deviation from the book.

   -- Bruce

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