[Solaris] top kernel usage

Hi,

We're having a server which is NOT a Linux server, it's a Unix machine, but it has an issue that could also be an issue on Linux, so my question is: what if the exact same issue would occur on Linux ?

The problem is this: for hours and possibly days, the kernel usage goes up to 30 to 40%, and it consistently stays there. This server in particular isn't very high on CPU power, but this means that for a long time, it has considerable amounts less to play with. Needless to say then is that idle drops to extreme low values, including staying at 0% for a long time.