make doesn't do anything about test speed. The App::Prove tools can help you though. Make sure you have a relatively new version of prove installed and read up on all its options with a focus on these–

        -j,  --jobs N          Run N test jobs in parallel (try 9.)
             --state=opts      Control prove's persistent state.
             --rc=rcfile       Process options from rcfile
             --rules           Rules for parallel vs sequential proces
+sing.
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