Re: [PATCH v3] coccicheck: process every source file at once

[Jacob Keller <jacob.keller@gmail.com>]

On Tue, Oct 2, 2018 at 1:07 PM Jacob Keller <jacob.e.keller@intel.com> wrote:
>
> From: Jacob Keller <jacob.keller@gmail.com>
>
> make coccicheck is used in order to apply coccinelle semantic patches,
> and see if any of the transformations found within contrib/coccinelle/
> can be applied to the current code base.
>
> Pass every file to a single invocation of spatch, instead of running
> spatch once per source file.
>
> This reduces the time required to run make coccicheck by a significant
> amount of time:
>
> Prior timing of make coccicheck
>   real    6m14.090s
>   user    25m2.606s
>   sys     1m22.919s
>
> New timing of make coccicheck
>   real    1m36.580s
>   user    7m55.933s
>   sys     0m18.219s
>
> This is nearly a 4x decrease in the time required to run make
> coccicheck. This is due to the overhead of restarting spatch for every
> file. By processing all files at once, we can amortize this startup cost
> across the total number of files, rather than paying it once per file.
>
> Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
> ---

Forgot to add what changed. I dropped the subshell and "||" bit around
invoking spatch.

Thanks,
Jake


>  Makefile | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index df1df9db78da..da692ece9e12 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -2715,10 +2715,8 @@ endif
>  %.cocci.patch: %.cocci $(COCCI_SOURCES)
>         @echo '    ' SPATCH $<; \
>         ret=0; \
> -       for f in $(COCCI_SOURCES); do \
> -               $(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS) || \
> -                       { ret=$$?; break; }; \
> -       done >$@+ 2>$@.log; \
> +       $(SPATCH) --sp-file $< $(COCCI_SOURCES) $(SPATCH_FLAGS) >$@+ 2>$@.log; \
> +       ret=$$?; \
>         if test $$ret != 0; \
>         then \
>                 cat $@.log; \
> --
> 2.18.0.219.gaf81d287a9da
>