Use proper pid in google benchmark walltime, expose CODSPEED_MODE as en option, fix compilation error with -Wall in instrumented mode

[GuillaumeLagrange]

Performance improvement is expected as the example is now compiled using CMAKE_BUILD_TYPE RelWithDebInfo

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #6 will improve performances by 72.05%

_{Comparing fix-walltime-pid (dc3c61d) with main (772a2db)}

Summary

⚡ 21 improvements

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	BarTest[MyFixture]	6.2 µs	3.6 µs	+74.91%
⚡	DoubleTest[MyTemplatedFixture, double]	6.3 µs	3.5 µs	+80.92%
⚡	FooTest[MyFixture]	6.3 µs	3.6 µs	+75.73%
⚡	IntTest[MyTemplatedFixture, int]	6.3 µs	3.5 µs	+79.43%
⚡	TestA[MyTemplate1, int]	6.3 µs	3.5 µs	+80.92%
⚡	TestB[MyTemplate2, int, double]	6.3 µs	3.5 µs	+81.6%
⚡	BM_Capture[int_string_test]	8.5 µs	3.8 µs	×2.3
⚡	BM_Capture[int_test]	7 µs	3.6 µs	+94.48%
⚡	BM_StringCopy	7.9 µs	3.9 µs	×2
⚡	BM_memcpy[4096]	15.2 µs	3.6 µs	×4.3
⚡	BM_memcpy[512]	8.4 µs	3.6 µs	×2.3
⚡	BM_memcpy[64]	7.6 µs	3.6 µs	×2.1
⚡	BM_memcpy[8192]	21.4 µs	3.6 µs	×6
⚡	BM_memcpy[8]	7.6 µs	3.6 µs	×2.1
⚡	BM_rand_vector	7 µs	3.6 µs	+92.62%
⚡	BM_Template1[int]	6.2 µs	3.6 µs	+73.22%
⚡	BM_Template1_Capture[int_string_test]	8.4 µs	3.7 µs	×2.3
⚡	BM_Template1_Capture[two_type_test, int, double]	8.5 µs	3.7 µs	×2.3
⚡	BM_Template2[int, double]	6.3 µs	3.7 µs	+72.05%
⚡	BM_Template[int]	9 µs	4.3 µs	×2.1
...	...	...	...	...

ℹ️ Only the first 20 benchmarks are displayed. Go to the app to view all benchmarks.

[codspeed-hq]

CodSpeed Walltime Performance Report

Merging #6 will improve performances by ×11,000,000,000

_{Comparing fix-walltime-pid (dc3c61d) with main (772a2db)}

Summary

⚡ 19 improvements
✅ 2 untouched benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	BarTest[MyFixture]	3.9 ns	0 ns	×3,200,000,000
⚡	DoubleTest[MyTemplatedFixture, double]	3.9 ns	0 ns	×3,300,000,000
⚡	FooTest[MyFixture]	3.8 ns	0 ns	×3,200,000,000
⚡	IntTest[MyTemplatedFixture, int]	3.7 ns	0 ns	×3,100,000,000
⚡	TestA[MyTemplate1, int]	3.7 ns	0 ns	×3,100,000,000
⚡	TestB[MyTemplate2, int, double]	3.9 ns	0 ns	×3,200,000,000
⚡	BM_Capture[int_string_test]	3.8 ns	0 ns	×3,000,000,000
⚡	BM_Capture[int_test]	3.8 ns	0 ns	×3,100,000,000
⚡	BM_StringCopy	42.6 ns	10 ns	×4.3
⚡	BM_memcpy[512]	44.8 ns	30 ns	+49.28%
⚡	BM_memcpy[64]	17.6 ns	6.1 ns	×2.9
⚡	BM_memcpy[8]	16.5 ns	6.1 ns	×2.7
⚡	BM_rand_vector	13.4 ns	0 ns	×11,000,000,000
⚡	BM_Template1[int]	4.5 ns	0.9 ns	×5.2
⚡	BM_Template1_Capture[int_string_test]	3.8 ns	0 ns	×3,100,000,000
⚡	BM_Template1_Capture[two_type_test, int, double]	3.8 ns	0 ns	×3,200,000,000
⚡	BM_Template2[int, double]	5.6 ns	0.9 ns	×6.5
⚡	BM_Template[int]	61.2 ns	9.7 ns	×6.3
⚡	BM_Template[std\:\:string]	227.3 ns	69.1 ns	×3.3