#!/usr/bin/perl -w
 #
 # hotkernel - sample on-CPU kernel-level functions and modules.
 #             Written using Perl and DTrace (Solaris 10 03/05)
 #
 # This samples the on-CPU function at 1001 Hertz, for a simple yet
 # effective kernel-level profiling tool for sampling exclusive function time.
 # The output will identify which function is on the CPU the most - which is
 # the hottest. See Notes/ALLexclusive_notes.txt for an explanation of
 # exclusive time.
 #
 # $Id: hotkernel 65 2007-10-04 11:09:40Z brendan $
 #
 # USAGE:        hotkernel [-hm]
 #
 #		-h              # help
 #		-m              # match modules, not functions
 #       eg,
 #		hotkernel       # sample kernel functions
 #		hotkernel -m    # sample kernel modules
 #
 # FIELDS:
 #		FUNCTION        Function name
 #		MODULE          Module name
 #		COUNT           Number of samples
 #		PCNT            Percentage of total samples
 #
 # COPYRIGHT: Copyright (c) 2006 Brendan Gregg.
 #
 # CDDL HEADER START
 #
 #  The contents of this file are subject to the terms of the
 #  Common Development and Distribution License, Version 1.0 only
 #  (the "License").  You may not use this file except in compliance
 #  with the License.
 #
 #  You can obtain a copy of the license at Docs/cddl1.txt
 #  or http://www.opensolaris.org/os/licensing.
 #  See the License for the specific language governing permissions
 #  and limitations under the License.
 #
 # CDDL HEADER END
 #
 # Author: Brendan Gregg  [Sydney, Australia]
 #
 # 29-Jun-2006	Brendan Gregg	Created this.
 # 29-Jun-2006	   "      "	Last update.
 #
 
 use strict;
 use Getopt::Std;
 
 #
 # Command Line Arguments
 #
 my $args;
 usage() if defined $ARGV[0] and $ARGV[0] eq "--help";
 getopts('hm') or usage();
 usage() if defined $main::opt_h and $main::opt_h;
 my $mods = defined $main::opt_m and $main::opt_m ? 1 : 0;
 
 #
 # Cleanup on signals
 #
 $SIG{INT} = \&cleanupsig;    # Ctrl-C
 $SIG{QUIT} = \&cleanupsig;   # Ctrl-\
 $SIG{TERM} = \&cleanupsig;   # TERM
 
 #
 # Declare DTrace script
 #
 my $dtrace = <	profile:::profile-1001hz
 	/arg0/
 	{
 		\@pc[arg0] = count();
 	}
 	dtrace:::END
 	{
 		printa("%a %\@d\\n", \@pc);
 	}
 '
 END
 
 #
 # Run DTrace, process output
 #
 my %Count;
 my $total;
 open DTRACE, "$dtrace |" or die "ERROR1: Can't run dtrace (perms?): $!\n";
 print "Sampling... Hit Ctrl-C to end.\n";
 while (my $line = <DTRACE>) {
     next if $line =~ /^\s*$/;
     my ($addr, $count) = split ' ', $line;
     my ($name, $offset) = split /\+/, $addr;
     next if $name eq "0x0";
     $name =~ s/\`.*// if $mods;
     $Count{$name} += $count;
     $total += $count;
 }
 close DTRACE;
 
 #
 # Print final report
 #
 printf "\n%-52s %8s %6s\n", $mods ? "MODULE" : "FUNCTION", "COUNT", "PCNT";
 foreach my $name (sort { $Count{$a} <=> $Count{$b} } keys %Count) {
     printf "%-52s %8d %5.1f%%\n", $name, $Count{$name},
                                   100 * $Count{$name} / ($total ? $total : 1);
 }
 
 #
 # Subroutines
 #
 sub cleanupsig {
 }
 sub usage {
     print STDERR "USAGE: hotkernel [-hm]\n";
     print STDERR "   eg,\n";
     print STDERR "       hotkernel       # sample kernel functions\n";
     print STDERR "       hotkernel -m    # sample kernel modules\n";
     exit 1;
 }