Re: [PATCH v4] devtools: parallelize ABI check

[David Marchand <david.marchand@redhat.com>]

On Wed, Jan 11, 2023 at 8:53 PM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> Generation and comparison of ABI dumps are done on multiple cores
> thanks to xargs -P0.
> It can accelerate this long step by 5 in my tests.
>
> xargs reports a global error if one of the process has an error.
>
> Running a shell function with xargs requires to export it.
> POSIX shell does not support function export except using an "eval trick".
> Required variables are also exported.
>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> Tested-by: Ferruh Yigit <ferruh.yigit@amd.com>
> diff --git a/devtools/check-abi.sh b/devtools/check-abi.sh
> index c583eae2fd..31eceb42e6 100755
> --- a/devtools/check-abi.sh
> +++ b/devtools/check-abi.sh
> @@ -34,20 +34,18 @@ else
>         ABIDIFF_OPTIONS="$ABIDIFF_OPTIONS --headers-dir2 $incdir2"
>  fi
>
> -error=
> -for dump in $(find $refdir -name "*.dump"); do
> +export newdir ABIDIFF_OPTIONS
> +export diff_func='run_diff() {
> +       dump=$1
>         name=$(basename $dump)
>         dump2=$(find $newdir -name $name)
>         if [ -z "$dump2" ] || [ ! -e "$dump2" ]; then
>                 echo "Error: cannot find $name in $newdir" >&2
> -               error=1
> -               continue
> -       fi
> +               return 1
> +       fi;

No need for ; here.
This can be fixed when applying (I tested both your patch and with
this small fix).


>         abidiff $ABIDIFF_OPTIONS $dump $dump2 || {
>                 abiret=$?
> -               echo "Error: ABI issue reported for 'abidiff $ABIDIFF_OPTIONS $dump $dump2'" >&2
> -               error=1
> -               echo
> +               echo "Error: ABI issue reported for abidiff $ABIDIFF_OPTIONS $dump $dump2" >&2
>                 if [ $(($abiret & 3)) -ne 0 ]; then
>                         echo "ABIDIFF_ERROR|ABIDIFF_USAGE_ERROR, this could be a script or environment issue." >&2
>                 fi
> @@ -57,8 +55,13 @@ for dump in $(find $refdir -name "*.dump"); do
>                 if [ $(($abiret & 8)) -ne 0 ]; then
>                         echo "ABIDIFF_ABI_INCOMPATIBLE_CHANGE, this change breaks the ABI." >&2
>                 fi
> -               echo
> +               return 1
>         }
> -done
> +}'
> +
> +error=
> +find $refdir -name "*.dump" |
> +xargs -n1 -P0 sh -c 'eval "$diff_func"; run_diff $0' ||
> +error=1
>
>  [ -z "$error" ] || [ -n "$warnonly" ]

For the record, on my system, calling this script is ~5 times faster:
- before
real    0m5,447s
user    0m4,497s
sys    0m0,937s

- after
real    0m1,202s
user    0m10,784s
sys    0m2,027s


> diff --git a/devtools/gen-abi.sh b/devtools/gen-abi.sh
> index f15a3b9aaf..61f7510ea1 100755
> --- a/devtools/gen-abi.sh
> +++ b/devtools/gen-abi.sh
> @@ -22,5 +22,6 @@ for f in $(find $installdir -name "*.so.*"); do
>         fi
>
>         libname=$(basename $f)
> -       abidw --out-file $dumpdir/${libname%.so*}.dump $f
> -done
> +       echo $dumpdir/${libname%.so*}.dump $f
> +done |
> +xargs -n2 -P0 abidw --out-file
> --
> 2.39.0
>

- before
real    0m8,237s
user    0m7,704s
sys    0m0,504s

- after
real    0m2,517s
user    0m14,145s
sys    0m0,766s


Ferruh, I am seeing quite different numbers for running those scripts
(clearly not of the minute order).
I switched to testing/building in tmpfs some time ago.
It requires a good amount of memory (I empirically allocated 40G), but
maybe worth a try for you?


In any case, this patch lgtm.
Acked-by: David Marchand <david.marchand@redhat.com>


-- 
David Marchand