kmem_stackinfo

Description

If the kmem_stackinfo variable is enabled in the /etc/system file at kernel thread creation time, the kernel thread stack is filled with a specific pattern instead of filled with zeros. During kernel thread execution, this kernel thread stack pattern is progressively overwritten. A simple count from the stack top until the pattern is not found gives a high watermark value, which is the maximum kernel stack space used by a kernel thread. This mechanism allows the following features:

• Compute the percentage of kernel thread stack really used (a high watermark) for current kernel threads in the system

• When a kernel thread ends, the system logs the last kernel threads that have used the most of their kernel thread stacks before dying to a small circular memory buffer

Data Type

Unsigned integer

Default

0 (disabled)

Range

0 (disabled) or 1 (enabled)

Dynamic?

Yes

Validation

None

When to Change

When you want to monitor kernel thread stack usage. Keep in mind that when kmem_stackinfo is enabled, the performance of creating and deleting kthreads is decreased. For more information, see Oracle Solaris Modular Debugger Guide.

Zone Configuration

This parameter must be set in the global zone.

Commitment Level

Unstable