Re: [PATCH 2/3] ci: do not use #processors+1 jobs, #processors is enough

[Thomas Huth <thuth@redhat.com>]

On 18/05/2021 10.41, Paolo Bonzini wrote:
> I could not reconstruct the origin of the $(($(nproc) + 1)) idiom,
> but I suspect it was there only to have a sensible result when nproc
> or getconf do not exist.  This can be achieved also with an "||".
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   .gitlab-ci.yml | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
> index 4bd1a91aa8..3f0d86cf0a 100644
> --- a/.gitlab-ci.yml
> +++ b/.gitlab-ci.yml
> @@ -17,7 +17,7 @@ include:
>     stage: build
>     image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
>     before_script:
> -    - JOBS=$(expr $(nproc) + 1)
> +    - JOBS=$(nproc || echo 1)

The basic idea of the "+ 1" was to make sure that there is always a thread 
that runs on a CPU while maybe another one is waiting for I/O to complete. 
This is suggested by various sites on the web, e.g.:

 
https://unix.stackexchange.com/questions/519092/what-is-the-logic-of-using-nproc-1-in-make-command

So not sure whether this patch here make sense ... I'd rather drop it.

  Thomas