Comparing a cache warm git grep vs command line grep shows significant differences in cpu & wall clock.

Any ideas how to improve this?

$ time git grep "\bseq_.*%p\W" | wc -l 112

real 0m4.271s user 0m15.520s sys 0m0.395s

$ time grep -r --include=*.[ch] "\bseq_.*%p\W" * | wc -l 112

real 0m1.164s user 0m0.847s sys 0m0.314s