Re: [Boost-build] b2 configuration checks take long time

Subject: Re: [Boost-build] b2 configuration checks take long time
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2018-08-29 19:24:29

AMDG

On 08/29/2018 01:13 PM, Mateusz Loskot via Boost-build wrote:
> I have a very simple libs/gil/test/image_view/Jamfile
> 
> ```
> import testing ;
> 
> project
>     : requirements
>     <include>$(BOOST_ROOT)
>     <include>..
>     ;
> 
> test-suite "boost-gil-test-image-view"
>     :
>     [ run collection.cpp ]
>     ;
> ```
> 
> The collection.cpp is just
> 
> ```
> int main() {}
> ```
> 
> In libs/gil/test, I run `b2 collection` first time.
> I run `b2 collection` again.
> 
> What may be the reason it takes 15-18 seconds until I see this?
> 

It's loading the xxx/build/ Jamfiles for all of boost,
not just your project.  It also scans all the xxx/include/
directories to set up the global include directory.

> ```
> Performing configuration checks
>     - default address-model    : 64-bit (cached)
>     - default architecture     : x86 (cached)
>     - symlinks supported       : yes (cached)
> ```
> 
> How can I speed up the b2 startup?
> 

Try inserting a Jamroot to block the extra work that Boost's
Jamroot is doing automatically.  This is a bad idea in
general, as the aforementioned work is important, but it
should be okay as long as you set up `b2 headers` beforehand
and do not use any separately compiled boost libraries.

> I'm observing this on WSL (Ubuntu Bionic, GCC 7.3), on very decent workstation.
> I have no access to Linux native host to compare if perhaps the issue is
> due to WSL filesystem poor performance.
> 

In Christ,
Steven Watanabe