Sadly, there is no longer a site in Perth itself.
However, you've got sites at Auchterarder, Crieff, Dunkeld, Pitlochry and Scone, plus probably others.
You'll find them listed in any Site Guide. Check the "Camp Site Search" here.
Faskally on the edge of Pitlochry is one of my favourite sites, beutifull location, good toilets, great walks, swimming pool and pub onsite with entertainment most nites.
Also Blair Athol Castle Park is very good,massive site great setting and great facilities