Add a new routine kvm_getcptime(3) for fetching the equivalent of

'kern.cp_time'.  For a live kernel it uses the sysctl.  For a crashdump,
it first checks to see if the kernel has a 'cp_time' global symbol.  If
it does, it uses that.  If that doesn't work, when it uses the recently
added kvm_getmaxcpu(3) and kvm_getpcpu(3) routines to walk all the CPUs
and sum up their counters.

MFC after:	1 week

1 files changed, 77 insertions, 0 deletions

diff --git a/lib/libkvm/kvm_getcptime.3 b/lib/libkvm/kvm_getcptime.3
new file mode 100644
index 0000000..2ddc272
--- /dev/null
+++ b/lib/libkvm/kvm_getcptime.3
@@ -0,0 +1,77 @@
+.\" Copyright (c) 2008 Yahoo!, Inc.
+.\" All rights reserved.
+.\" Written by: John Baldwin <jhb@FreeBSD.org>
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the author nor the names of any co-contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd August 19, 2008
+.Dt KVM_GETCPTIME 3
+.Os
+.Sh NAME
+.Nm kvm_getcptime
+.Nd fetch global CPU time statistics
+.Sh LIBRARY
+.Lb libkvm
+.Sh SYNOPSIS
+.In sys/param.h
+.In sys/resource.h
+.In sys/sysctl.h
+.In kvm.h
+.Ft int
+.Fn kvm_getcptime "kvm_t *kd" "long *cp_time"
+.Sh DESCRIPTION
+The
+.Fn kvm_getcptime
+function stores the global CPU time statistics from the kernel
+.Fa kd
+in the array of counters pointed to by
+.Fa cp_time .
+Note that
+.Fa cp_time
+should point to an array of
+.Dv CPUSTATES
+long integers.
+The format of the counters is identical to that output by the
+.Va kern.cp_time
+sysctl.
+.Sh CACHING
+This function caches the nlist values for various kernel variables which it
+reuses in successive calls.
+You may call the function with
+.Fa kd
+set to
+.Dv NULL
+to clear this cache.
+.Sh RETURN VALUES
+The
+.Nm kvm_getcptime
+function returns 0 on success and -1 on failure.
+If an error occurs,
+then an error message may be retrieved via
+.Xr kvm_geterr 3 .
+.Sh SEE ALSO
+.Xr kvm 3