[Mesa-dev] [PATCH] src: replace RTLD_NOW with RTLD_LAZY

[Jan Vesely]

On Sat, 2016-08-06 at 18:52 +0200, ⚛ wrote:
> On Sat, Aug 6, 2016 at 5:52 PM, Jan Vesely <jan.vesely at rutgers.edu>
> wrote:
> > 
> > The situation I'm concerned about is as
> > follows:
> > 1.) mesa builds fine using existing build environment.
> > 
> > 2.) I update LLVM. This update changes symbols (function parameter
> > changed type, a function was moved to header, or devirtualization
> > pass
> > did a better job, ...)
> > 
> > I want to know whether this happened and mesa rebuild is necessary.
> 
> After updating LLVM:
> 
> $ qlist mesa | grep \\.so | LD_PRELOAD=/usr/\${LIB}/libGL.so xargs
> ldd
> -d -r | grep defined
> 
> qlist is a Gentoo-specific command, other Linux distributions might
> have an equivalent program under a different name.

you're missing the point. I can add other checks to my setup (or just
keep local revert of the patch), though I'd prefer not to do that.

my point is that it makes the code less robust for questionable
benefit, 6M instructions should be <1ms on modern CPU, and probably
within measurement error even for glxinfo. if you show other benefits
the balance changes.

of course, it's not my decision to make, so feel free to ignore any of
my input.

Jan

PS: please do not contact me off-list, I'm not interested in non-
technical discussion

> 
> > 
> > surely most llvm symbols are used immediately, but if optimizations
> > like shader cache are present it can take some time before the
> > compiler
> > path is exercised, postponing failed symbol lookups well into the
> > future.
-- 
Jan Vesely <jan.vesely at rutgers.edu>
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