Solaris Performance and Tools: DTrace and MDB Techniques for Solaris 10 and OpenSolaris

6.15. Kernel Memory with kstat

You can determine the amount of kernel memory by using the Solaris kstat command and multiplying the pp_kernel by the system's base page size. The computed output is in bytes; in this example, the kernel is using approximately 250 Mbytes of memory.

$ kstat unix::system_pages:pp_kernel module: unix instance: 0 name: system_pages class: pages pp_kernel 64102 $ pagesize 4096 $ bc 64102*4096 262561792

A general rule is that you would expect the kernel to use approximately 15% of the system's total physical memory. We've seen this to be true in more than 90% of observed situations. Exceptions to the rule are cases, such as an in-kernel Web server cache, in which the majority of the workload is kernel based. Investigate further if you see large kernel memory sizes.