Rate GSM::SMS
GSM::SMS      321/s       --
Device::Gsm   342/s       7%
Dev::Gsm_opt  500/s      56%
Subst/Subst   519/s      62%   # This was called My_code above
Subst/Array   527/s      64%   # i.e. packwithsubst / unpackwitharray
Array/Subst   777/s     142%
Array/Array   808/s     152%