#!/usr/bin/perl
# llobdstat is a utility that parses OST statistics files
# found at e.g. obdfilter.<ostname>.stats or osc.<ostname>*.stats.
# It is mainly useful to watch the bandwidth usage over time.

my $pname = $0;
my $obddev = "";
my $obdstats = "stats";
my $statspath = "None";
my $statsname = $obdstats;
my $interval = 0;
my $counter = 999999999;
my $debug = 0;
my $have_readkey = 1;
my $width = 120;
my $height = 25;

sub usage()
{
	print STDERR "Monitor read/write bandwidth of an OST device\n";
	print STDERR "Usage: $pname [-h] [-i <interval>] [-v] <ost_name> [<interval> [<count>}]\n";
	print STDERR "       stats_file : Lustre 'stats' file to watch\n";
	print STDERR "       -d         : debug mode\n";
	print STDERR "       -h         : help, display this information\n";
	print STDERR "       -i interval: polling period in seconds\n";
	print STDERR "       -n count   : number of samples printed\n";
	print STDERR "example: $pname -i 5 lustre-OST0000\n";
	print STDERR "Use CTRL + C to stop statistics printing\n";
	exit 1;
}

# Command line parameter parsing
use Getopt::Std;
getopts('dhi:n:') or usage();
usage() if $opt_h;
$debug = $opt_d if $opt_d;
$interval = $opt_i if $opt_i;
$counter = $opt_n if $opt_n;

my $i = 0;
foreach (@ARGV) {
	if ($i == 0) {
		$obddev = $_;
		$obddev =~ s/\./\//g;
	} elsif ($i == 1) {
		$interval = $_;
	} elsif ($i == 2) {
		$counter = $_;
	} else {
		print "ERROR: extra argument $_\n";
		usage();
	}
	$i++;
}
if ( !$obddev ) {
	print "ERROR: Need to specify stats_file\n";
	usage();
}

# Process arguments
my $procpath = "/proc/fs/lustre";
foreach my $param ( "$obddev", "$obddev*/$obdstats", "$obddev*/*/$obdstats",
		    "*/$obddev*/$obdstats", "*/*/$obddev*/$obdstats" ) {
	if ($debug) {
		printf "trying $procpath/$param\n";
	}
	my $st = glob("$procpath/$param");
	if ( -f "$st" ) {
		$statspath = $st;
		$statsname = `lctl list_param $param | head -n 1`;
		if ($debug) {
			print "using $statspath\n"
		}
		last;
	}
}
if ($statspath =~ /^None$/) {
	# server stats are currently in /proc/fs/lustre, but may move eventually
	$procpath = "/sys/kernel/debug/lustre";

	foreach my $param ( "$obddev", "$obddev*/$obdstats", "$obddev*/*/$obdstats",
			    "*/$obddev*/$obdstats", "*/*/$obddev*/$obdstats" ) {
		if ($debug) {
			print "trying $procpath/$param\n";
		}
		$st = glob("$procpath/$param");
		if ($debug) {
			print "glob $procpath/$param = $st\n";
		}
		if (-f "$st") {
			$statspath = $st;
			$statsname = `lctl list_param $param | head -n 1`;
			if ($debug) {
				print "using $statspath\n"
			}
			last;
		}
	}
	if ($statspath =~ /^None$/) {
		die "Cannot locate stat file for: $obddev\n";
	}
}

# check if Term::ReadKey is installed for efficient tty size, but OK if missing
eval "require Term::ReadKey" or $have_readkey = 0;
if ($debug) {
	print "have_readkey=$have_readkey\n";
}
if ($have_readkey) {
	eval "use Term::ReadKey";
}

print "$pname on $statsname\n";

my %cur;
my %last;

# Removed some statstics like open, close that the OST doesn't contain.
# To add statistics parameters one needs to specify parameter names in the
# below declarations in the same sequence.
my ($read_bytes, $write_bytes, $create, $destroy, $statfs, $punch, $timestamp) =
	("read_bytes", "write_bytes", "create", "destroy", "statfs", "punch",
	 "snapshot_time");

my @extinfo = ($create, $destroy, $statfs, $punch);
my %shortname = ($create => "cx", $destroy => "dx", $statfs => "st", $punch => "pu");

# read statistics from the stats file.
# This subroutine gets called after every interval specified by user.
sub readstat()
{
    my $prevcount;
    my @iodata;

    seek STATS, 0, 0;
    while (<STATS>) {
        chop;
        @iodata = split(/\s+/, $_);
        my $name = $iodata[0];

        $prevcount = $cur{$name};
        if (defined($prevcount)) {
            $last{$name} = $prevcount;
        }
        if ($name =~ /^$timestamp/) {
            $cur{$name} = $iodata[1];
        } elsif ($name =~ /^$read_bytes$/) {
	    if (defined($cur{"read_ops"})) {
		$last{"read_ops"} = $cur{"read_ops"};
	    }
            $cur{"read_ops"} = $iodata[1];
            $cur{$name} = $iodata[6];
	} elsif ($name =~ /^$write_bytes$/) {
	    if (defined($cur{"write_ops"})) {
		$last{"write_ops"} = $cur{"write_ops"};
	    }
            $cur{"write_ops"} = $iodata[1];
            $cur{$name} = $iodata[6];
        } else {
            $cur{$name} = $iodata[1];
        }
    }
}

# process stats information read from the stats file.
# This subroutine gets called after every interval specified by user.
sub process_stats()
{
    my $delta;
    my $data;
    my $last_time = $last{$timestamp};
    if (!defined($last_time)) {
        printf "Read: %.1f GiB, Write: %.1f GiB, cr: %lu dx: %lu, st: %lu, pu: %lu\n",
            $cur{$read_bytes} / (1 << 30), $cur{$write_bytes} / (1 << 30),
            $cur{$create}, $cur{$destroy}, $cur{$statfs}, $cur{$punch};
	print "[NOTE: cx: create, dx: destroy, st: statfs, pu: punch]\n\n";
    } else {
        my $timespan = $cur{$timestamp} - $last{$timestamp};
        my $rtot = ($cur{$read_bytes} - $last{$read_bytes}) / (1 << 20);
        my $riops = ($cur{"read_ops"} - $last{"read_ops"}) / $timespan;
        my $rrate = $rtot / $timespan;
        my $wtot = ($cur{$write_bytes} - $last{$write_bytes}) / (1 << 20);
        my $wiops = ($cur{"write_ops"} - $last{"write_ops"}) / $timespan;
        my $wrate = $wtot / $timespan;

	# this is printed once per screen, like vmstat/iostat
        if ($count++ % ($height - 2) == 0) {
            print "Timestamp  Read-MiB RdMiB/s WriteMiB WrMiB/s RdIOPS WrIOPS\n";
            print "---------- -------- ------- -------- ------- ------ ------\n";
	    if ($have_readkey) {
		($width, $height, $wpixels, $hpixels) = GetTerminalSize();
	    } else {
		($height, $width) = split / /, `stty size 2> /dev/null`;
		#$width = 120 if ! $width
	    }
        }
        # This print repeats after every interval.
        printf "%10lu %8.1f %7.1f %8.1f %7.1f %6lu %6lu",
               $cur{$timestamp}, $rtot, $rrate, $wtot, $wrate, $riops, $wiops;

        $delta = $cur{$getattr} - $last{$getattr};
        if ( $delta != 0 ) {
            $rdelta = int ($delta/$timespan);
            print " ga:$delta,$rdelta/s";
        }

        for $data ( @extinfo ) {
            $delta = $cur{$data} - $last{$data};
            if ($delta != 0) {
                print " $shortname{$data}:$delta";
            }
        }
        print "\n";
        $| = 1;
    }
}

#Open the stat file with STATS
open(STATS, $statspath) || die "Cannot open $statspath: $!\n";
do {
    # read the statistics from stat file.
    readstat();
    process_stats();
    if ($interval) {
        sleep($interval);
        %last = %cur;
    }
    # Repeat the statistics printing after every "interval" specified in
    # command line, up to counter times, if specified
} while ($interval && $counter-- > 0);
close STATS;