Gunnar seems to be a German/Scandinavian name which enjoys particular popularity in Sweden. My father is from Baramulla, Kashmir, India, my mother from Riga, Latvia. They met in Germany, I was born in Cologne and this seems to be the compromise they came up with. The name might be a derivative of Gundahar where Gunda = war and Har = lord. More peaceful interpretations are possible like Gun = excellent/talented and Nar = person.

You can also check out the significance of S. and Bali if interested.