Optimization flags

[Valentin V. Bartenev]

On Friday 08 July 2016 14:44:00 Lantos István wrote:
> The default --with-cc-opt flags for Nginx are these:
> 
> *--with-cc-opt='-g -O2 -fstack-protector-strong -Wformat
> > -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2'*
> >
> 
> However I added more optimizations, which are against the standard:
> 
> *--with-cc-opt='-g -Ofast -march=native -ffast-math
> > -fstack-protector-strong -Wformat -Werror=format-security
> > -Wp,-D_FORTIFY_SOURCE=2'*
> >
> 
> So far I don't experience any bug, but I do have a higher benchmark:
> 380-450 req/s compared to the original 290-310 req/s with cached
> Node/Express app on my laptop.
> 
> Is it safe to use -O3 or -Ofast flags with Nginx?

Usually it is safe.  You can run tests: http://hg.nginx.org/nginx-tests/

> 
> Is it possible to build Nginx with clang? If so, should I symlink it to gcc
> (I use Docker, this way gcc executable is trashed) or is there a way to
> define the compiler with a flag?

  --with-cc=

  wbr, Valentin V. Bartenev