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KGMON(8) System Manager's Manual KGMON(8)

kgmongenerate a dump of the operating system's profile buffers

kgmon [-bhpr] [-c cpuid] [-M core] [-N system]

kgmon is a tool used when profiling the operating system. When no arguments are supplied, kgmon indicates the state of per-CPU operating system profilings as “running”, “off”, or “not configured” (see config(8)). If the -p flag is specified, kgmon extracts profile data from the operating system and produces a file for each CPU suitable for later analysis by gprof(1).

The options are as follows:

Resume the collection of profile data.
Operate on the CPU specified by cpuid, instead of all of them.
Stop the collection of profile data.
Extract values associated with the name list from the specified core instead of the default /dev/kmem.
Extract the name list from the specified system instead of the default /bsd.
Dump the contents of the profile buffers into a gmon-<id>.out file, where “id” is the ID of the CPU.
Reset all the profile buffers. If the -p flag is also specified, the profile files are generated before the buffers are reset.

If neither -b nor -h is specified, the state of profiling collection remains unchanged. For example, if the -p flag is specified and profile data is being collected, profiling will be momentarily suspended, the operating system profile buffers will be dumped, and profiling will be immediately resumed.

kgmon requires the ability to open /dev/kmem which may be restricted based upon the value of the kern.allowkmem sysctl(8).

default system
default memory

Users with only read permission on /dev/kmem cannot change the state of profiling collection. They can get profile files with the warning that the data may be inconsistent if profiling is in progress.

gprof(1), config(8)

The kgmon command appeared in 4.2BSD.

September 25, 2016 OpenBSD-6.6