Fix kernel profiling on MP systems by using per-CPU buffers and teach

kgmon(8) to deal with them, this time without public header changes.

Previously various CPUs were iterating over the same global buffer at
the same time to modify it and never ended.

This diff includes some ideas submited by Thor Simon to NetBSD via miod@.

ok deraadt@, mikeb@, haesbaert@

1 files changed, 6 insertions, 8 deletions

diff --git a/usr.sbin/kgmon/kgmon.8 b/usr.sbin/kgmon/kgmon.8
index 6f12062f5c5..f3229800a46 100644
--- a/usr.sbin/kgmon/kgmon.8
+++ b/usr.sbin/kgmon/kgmon.8
@@ -1,4 +1,4 @@
-.\" $OpenBSD: kgmon.8,v 1.12 2013/02/12 08:06:22 mpi Exp $
+.\" $OpenBSD: kgmon.8,v 1.13 2013/03/12 09:37:16 mpi Exp $
 .\" Copyright (c) 1983, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -27,9 +27,8 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)kgmon.8	8.1 (Berkeley) 6/6/93
-.\"	$Id: kgmon.8,v 1.12 2013/02/12 08:06:22 mpi Exp $
 .\"
-.Dd $Mdocdate: February 12 2013 $
+.Dd $Mdocdate: March 12 2013 $
 .Dt KGMON 8
 .Os
 .Sh NAME
@@ -38,6 +37,7 @@
 .Sh SYNOPSIS
 .Nm kgmon
 .Op Fl bhpr
+.Op Fl c Ar cpuid
 .Op Fl M Ar core
 .Op Fl N Ar system
 .Sh DESCRIPTION
@@ -45,7 +45,7 @@
 is a tool used when profiling the operating system.
 When no arguments are supplied,
 .Nm kgmon
-indicates the state of operating system profiling as
+indicates the state of per-CPU operating system profilings as
 .Dq running ,
 .Dq off ,
 or
@@ -117,10 +117,8 @@ Users with only read permission on
 .Pa /dev/kmem
 cannot change the state
 of profiling collection.
-They can get a
-.Pa gmon.out
-file with the warning that the data may be
-inconsistent if profiling is in progress.
+They can get profile files with the warning that the data may be inconsistent
+if profiling is in progress.
 .Sh SEE ALSO
 .Xr gprof 1 ,
 .Xr config 8