01-19-2007
0% is very unsual, low single digits on an idle machine is not.
continuous 100% is bad, you may get a process grabbing everything that is available, but as Corona said, unless a process or thread it is scheduled with a higher than normal prority or is non-preemptable this should not cause the system major problems, it will just have to share with everyone else. An example of this would be something like running a large build which will probably grab every idle cycle you have.
If a server it "normally" using 100% of CPU it means that it is under spec for the workload ( any of memory or cpu or IO depending on the workload ) OR has one or more runnaway process that are hogging cpu.
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CPU(1) General Commands Manual CPU(1)
NAME
cpu - connection to cpu server
SYNOPSIS
cpu [ -h server ] [ -c cmd args ... ]
DESCRIPTION
Cpu starts an rc(1) running on the server machine, or the machine named in the $cpu environment variable if there is no -h option. Rc's
standard input, output, and error files will be /dev/cons in the name space where the cpu command was invoked. Normally, cpu is run in an
81/2(1) window on a terminal, so rc output goes to that window, and input comes from the keyboard when that window is current. Rc's cur-
rent directory is the working directory of the cpu command itself.
The name space for the new rc is an analogue of the name space where the cpu command was invoked: it is the same except for architecture-
dependent bindings such as /bin and the use of fast paths to file servers, if available.
If a -c argument is present, the remainder of the command line is executed by rc on the server, and then cpu exits.
The name space is built by running /usr/$user/lib/profile with the root of the invoking name space bound to /mnt/term. The service envi-
ronment variable is set to cpu; the cputype and objtype environment variables reflect the server's architecture.
FILES
The name space of the terminal side of the cpu command is mounted on the CPU side on directory /mnt/term.
SOURCE
/sys/src/cmd/cpu.c
SEE ALSO
rc(1), 81/2(1)
BUGS
Binds and mounts done after the terminal lib/profile is run are not reflected in the new name space.
CPU(1)