[tarantool-patches] Re: [PATCH v2 2/3] Add LTO support

[Konstantin Osipov <kostja@tarantool.org>]

* Alexander Turenko <alexander.turenko@tarantool.org> [18/10/15 10:15]:
> From: AKhatskevich <avkhatskevich@tarantool.org>
> 
> Added -DENABLE_LTO=ON/OFF cmake option, OFF by default.
> 
> LTO speeds up cpu-intensive workloads by up to 20% (see [1] and [2]).
> 
> Requirements for LTO enabling:

to enable LTO, not "for LTO enabling".

The same applies to cmake message:
> +if(CMAKE_VERSION VERSION_LESS 3.9)
> +    message(FATAL_ERROR "cmake >= 3.9 is needed for LTO enabling")
> +endif()


> +
> +# Set 'CMP0069 NEW' behaviour for this project to support
> +# compilers other than Intel Compiler and suppress cmake
> +# warnings on the unset policy.
> +cmake_policy(SET CMP0069 NEW)

Please describe what this policy is about, not only just what it
is for.

> +
> +# Retain 'CMP0069 NEW' behaviour after
> +# 'cmake_minimum_required(VERSION ...) in subprojects to
> +# avoid cmake warnings on the unset policy.
> +set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)


-- 
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov