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




On 02.10.18 22:18, Jacob Keller wrote:
> On Tue, Oct 2, 2018 at 1:07 PM Jacob Keller <jacob.e.keller@xxxxxxxxx> wrote:
>>
>> From: Jacob Keller <jacob.keller@xxxxxxxxx>
>>
>> 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@xxxxxxxxx>
>> ---
> 
> 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
>>

Wouldn't the following be even simpler?

diff --git a/Makefile b/Makefile
index 5c8307b7c479..a37b2724d526 100644
--- a/Makefile
+++ b/Makefile
@@ -2701,12 +2701,7 @@ 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; \
-       if test $$ret != 0; \
+       if ! $(SPATCH) --sp-file $< $(COCCI_SOURCES) $(SPATCH_FLAGS)
>$@+ 2>$@.log; \
        then \
                cat $@.log; \
                exit 1; \

Cheers,
Beat