Re: [PATCH 2/3] selftest/powerpc: Add flags.mk to support pmu buildable

[Madhavan Srinivasan <maddy@linux.ibm.com>]

On 4/29/24 7:39 PM, Michael Ellerman wrote:
> Madhavan Srinivasan <maddy@linux.ibm.com> writes:
>> When running `make -C powerpc/pmu run_tests` from top level selftests
>> directory, currently this error is being reported
>>
>> make: Entering directory '/home/maddy/linux/tools/testing/selftests/powerpc/pmu'
>> Makefile:40: warning: overriding recipe for target 'emit_tests'
>> ../../lib.mk:111: warning: ignoring old recipe for target 'emit_tests'
>> gcc -m64    count_instructions.c ../harness.c event.c lib.c ../utils.c loop.S  -o /home/maddy/selftest_output//count_instructions
>> In file included from count_instructions.c:13:
>> event.h:12:10: fatal error: utils.h: No such file or directory
>> 12 | #include "utils.h"
>>    |          ^~~~~~~~~
>> compilation terminated.
>>
>> This is due to missing of include path in CFLAGS. That is, CFLAGS and
>> GIT_VERSION macros are defined in the powerpc/ folder Makefile which
>> in this case not involved.
>>
>> To address the failure incase of executing specific sub-folder test directly,
>> a new rule file has been addded by the patch called "flags.mk" under
>> selftest/powerpc/ folder and is linked to all the Makefile of powerpc/pmu
>> sub-folders.
> This patch made my selftest build go from ~10s to ~50s !
>
> I tracked it down to "git describe" being run hundreds of times.
>
>> diff --git a/tools/testing/selftests/powerpc/flags.mk b/tools/testing/selftests/powerpc/flags.mk
>> new file mode 100644
>> index 000000000000..28374f470126
>> --- /dev/null
>> +++ b/tools/testing/selftests/powerpc/flags.mk
>> @@ -0,0 +1,12 @@
>> +#This checks for any ENV variables and add those.
>> +
>> +#ifeq ($(GIT_VERSION),)
>   
> This isn't right, # is a comment in make syntax, so this line is just a
> comment. It needs to be "ifeq".

oops, my bad :(
But nice catch. Thanks

Maddy


>
>> +GIT_VERSION = $(shell git describe --always --long --dirty || echo "unknown")
>   
> Using '=' here means Make re-runs the command every time the variable is
> used. Previously that was OK because the variable was set once and then
> exported. But now that it's a Make variable in each file it leads to
> "git describe" being run a few hundred times.
>
> I've squashed in those fixes, no need to send a v2.
>
> cheers