On 2019-09-23 11:36, Ray Kinsella wrote:
On 23/09/2019 08:23, Thomas Monjalon wrote:
20/09/2019 09:38, Ray Kinsella:
On 19/09/2019 16:16, Bruce Richardson wrote:
On Thu, Sep 19, 2019 at 02:28:04PM +0100, Ray Kinsella wrote:
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.
In the general case yes, but mainly it helps if you have a large number of
cores. For anyone building in a CI with only a couple of cores, meson+ninja
isn't going to help much.
/Bruce
Very true, and I completely acknowledge that LTO adds compilation time.
I would just like to see it in or out, not another build time option.
Please can we get some numbers to understand how longer it is?
I will note here, that it will always be a function of the number of
object files involved. We should measure it now to understand ...
On my system the non-LTO from-scratch build takes about one minute. With
LTO enabled, it takes about five minutes.
In addition, it makes our application *run* slower as well.
This reinforces past experience I have with LTO - it's more cool than
useful, unless you care much about the resulting code size.
