"make check" times

[DJ Delorie]

Pinging this ancient patch, now that I've finished the build times
report which answers the questions asked about this:

Original patch thread:
https://sourceware.org/pipermail/libc-alpha/2019-July/105187.html
Build times report thread:
https://sourceware.org/pipermail/libc-alpha/2020-March/111782.html

DJ Delorie <dj@redhat.com> writes:
> While digging for some low-hanging fruit in "make" times, I did this:
>
> diff --git a/scripts/merge-test-results.sh b/scripts/merge-test-results.sh
> index 919bbae253..7088ef6996 100755
> --- a/scripts/merge-test-results.sh
> +++ b/scripts/merge-test-results.sh
> @@ -35,7 +35,11 @@ case $type in
>      subdir=${subdir:+$subdir/}
>      for t in "$@"; do
>        if [ -s "$objpfx$t.test-result" ]; then
> -	head -n1 "$objpfx$t.test-result"
> +	  #head -n1 "$objpfx$t.test-result"
> +	  exec 6<"$objpfx$t.test-result"
> +	  read line <&6
> +	  echo $line
> +	  exec 6<&-
>        else
>  	echo "UNRESOLVED: $subdir$t"
>        fi
>
> That one instance of "head" is called over 6000 times per "make
> check", and as it's the only non-builtin in that script, it adds about
> 11 seconds of overhead compared to just reading that one line with
> builtins.
>
> My question here is: how much of a time savings is worth the
> complexity of said savings?