I think it needs a small change to match the \d, but yours is still fastest: 
    #               vv
    $message =~ s[\{\\d(\d+)\}][ substr int( rand 1e9 ), 0, $1 ]ge;


               Rate    mca_func toolic_func    buk_func
mca_func    41051/s          --        -36%        -56%
toolic_func 64558/s         57%          --        -30%
buk_func    92678/s        126%         44%          --

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In reply to Re^2: Speed Improvement by toolic
in thread Speed Improvement by Nar

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