I dare bet that hping is on your path when the script is run from CLI, but isn't when run by cron, try something like this in your crontab

/1 * * * * . $HOME/.profile; /root/scripts/perf/test.pl > /tmp/test.tx
+t 2>&1
[download]

On reflection, methinx there's also a typo - /1 isn't, AFAIK, valid crontab syntax.