[dpdk-dev] [PATCH v2 01/10] build: add an option to enable LTO build

Ray Kinsella mdr at ashroe.eu
Thu Sep 19 15:28:04 CEST 2019

On 19/09/2019 13:35, Andrzej Ostruszka wrote:
> On 9/18/19 3:32 PM, Ray Kinsella wrote:
> Compilation time is much longer.  In a normal hack|fix/compile/repeat
> cycle with "compile" part being simple "make" the link time might be a
> bit annoying.  So I imagine keeping LTO off for the most part of the dev
> cycle and then at the end when doing release/cleanup turn LTO on - to
> either get release build ready or to get some set of warnings that you
> address before yet another attempt to release build.  

Well look, I would say a few things.

1. I see build times going down dramatically with Meson/Ninja in any case.
2. You don't want any false positivess - i.e. misleading the contributor
into thinking their code builds fine, and then someone switches on LTO
and suddenly there is a problem that was missed (and hopefully gets
caught by CI) - and BTW I have seen these LTO specific issues in the past.

I strongly believe we will make all our lives easier, by having as few
ways of building DPDK as possible.

> By the way - this
> make config option is equivalent to meson 'b_lto' option, which by
> default is off, so we have similar behaviour in both build types.
> Regards
> Andrzej
> PS. I assumed that you've meant "LTO" not "GSO" - if not, then please
> explain what you've meant.

Your are correct, GSO was on my mind apologies.

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