the different length of your results, and especially the trailing "M" in the last line made me suspect
gettimeofday doesn't return integers. A look into
Time::HiRes confirms
gettimeofday ()
In array context returns a two-element array with the seconds and microseconds since the epoch. In scalar context returns floating seconds like Time::HiRes::time()
print evaluates its arguments in array context. So you could either change
$, (
$OUTPUT_FIELD_SEPARATOR) to somethng visible, or force scalar context by printing
scalar gettimeofday or
gettimeofday+0.