> Hi Stephen,
>
> The userspace fastpath backed by DPDK, more than other OVS components,
> performs a lot worse when optimizations are disabled. We ended up
> recommending "extreme" optimization flags in INSTALL.md ("-O3
> -march=native", ok if you don't need to run your build elsewhere).
>
> That said, autoconf by default builds with CFLAGS="-g -O2", but if you
> supply your own CFLAGS somehow, the default is overridden (Do not
> quote me on this, I'm not an autoconf expert. See
> https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-
> 2.69/html_node/C-Compiler.html#C-Compiler
> and http://www.gnu.org/software/autoconf/manual/autoconf-
> 2.66/html_node/Preset-Output-Variables.html).
Ahhh. Yes, once I manually specified the optimization flags defined in the
Makefile I was able to get expected performance. Just another funny side effect
of Autotools I guess.
> Users are not supposed to see OVS_CFLAGS: that was introduced by
> Thomas in the commit you linked to avoid overwriting user provided
> CFLAGS (it should be used by the autoconf scripts only). I believe you
> can use CFLAGS for all practical purposes.
The use of the OVS_CFLAGS was purely coincidental. I don't think it affect
anything.
> To add verbosity to make the "V=1" argument can be used. This will
> display the whole command line used to invoke the compiler.
>
> Hope this helped,
It did. Appreciate it.
>
> Daniele
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