#!/bin/sh
# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
#
#  perf-record.sh - a convenience script to launch perf record
#  Copyright (C) 2018  Viktor Rosendahl <viktor.rosendahl@gmail.com>
#
#  This file is dual licensed: you can use it either under the terms of
#  the GPL, or the BSD license, at your option.
#
#   a) This program is free software; you can redistribute it and/or
#      modify it under the terms of the GNU General Public License as
#      published by the Free Software Foundation; either version 2 of the
#      License, or (at your option) any later version.
#
#      This program is distributed in the hope that it will be useful,
#      but WITHOUT ANY WARRANTY; without even the implied warranty of
#      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#      GNU General Public License for more details.
#
#      You should have received a copy of the GNU General Public
#      License along with this library; if not, write to the Free
#      Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
#      MA 02110-1301 USA
#
#  Alternatively,
#
#   b) 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.
#
#      THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
#
cmd=$(basename $0)
SAMPLE_RATE_PROCFILE="/proc/sys/kernel/perf_event_max_sample_rate"

# These are the default events that we will try to use
default_events="power:cpu_frequency power:cpu_idle sched:sched_kthread_stop sched:sched_kthread_stop_ret sched:sched_migrate_task sched:sched_move_numa sched:sched_pi_setprio sched:sched_process_exec sched:sched_process_exit sched:sched_process_fork sched:sched_process_free sched:sched_process_wait sched:sched_stick_numa sched:sched_swap_numa sched:sched_switch sched:sched_wait_task sched:sched_wake_idle_without_ipi sched:sched_wakeup sched:sched_wakeup_new sched:sched_waking cpu-cycles"

usage()
{
    echo "Usage:\n"$cmd" [<options>]"
    echo "\t-h|--help\t\tDisplay this help information"
    echo "\t-s|--sleep <N>\t\tSleep N seconds before terminating trace"
    echo "\t-m|--memory <N>\t\tUse a buffer of N megatbytes]"
    echo "\t-n|--no-callgraph\tDo not record callgraphs"
    echo "\t-f|--frame-ponter\tUse frampointer callgraphs"
    echo "\t-x|--max-freq <N>\tSet the max sample rate to N"
    echo "\t-e|--event E\t\tAdd event E to the events to be traced"
    echo "\t-r|--realtime\t\tRun with SCHED_FIFO, priority 99"
    echo "\t-p|--rt-priority <P>\tRun with SCHED_FIFO, priority N"
    echo "\t-t|--stack-size <S>\tUse S bytes as stack size for callgraphs"
}

recording_msg()
{
    echo "Recording with:\n"$perf_cmd
}

timeout_stop_msg()
{
    echo "Timeout reached, stopped recording"
}

perf_cmd="perf record"

bufsize_opt=""
timeout_opt=""
callgraph_opt=""
sample_freq_opt="100000"
use_rt=""
rt_priority="99"
stack_size="20480"

while [ "$1" != "" ]; do
    case $1 in
	-h | --help )
	    usage
	    exit 0
	    ;;
	-s | --sleep )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    timeout_opt=$2
	    shift
	    ;;
	-m | --memory )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    bufsize_opt=$2
	    shift
	    ;;
	-n | --no-callgraph )
	    callgraph_opt="none"
	    ;;
	-f | --frame-pointer )
	    callgraph_opt="fp"
	    ;;
	-x | --max-freq )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    sample_freq_opt=$2
	    shift
	    ;;
	-e | --event )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    event=$2
	    default_events="$default_events $event"
	    shift
	    ;;
	-r | --realtime )
	    use_rt="yes"
	    ;;
	-p | --rt-priority )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    rt_priority=$2
	    shift
	    use_rt="yes"
	    ;;
	-t | --stack-size )
	    if [ $# -lt 2 ];then
		usage
		exit 0
	    fi
	    stack_size=$2
	    shift
	    ;;
	* )
	    usage
	    exit 0
	    ;;
    esac
    shift
done

# Check that each of the default events are supported and add them to the perf
# command
perflist=$(perf list|awk '{print $1}')
for event in $default_events
do
    for levent in $perflist
    do
	if [ "$event" = "$levent" ];then
	    perf_cmd="$perf_cmd -e $event"
	fi
    done
done

if [ -z $bufsize_opt ];then
    memtotal=$(cat /proc/meminfo|grep MemTotal:|awk '{print $2}')
    nrcpus=$(cat /proc/cpuinfo|awk '$1=="processor" {nrcpus+=1} END {print nrcpus}')

    wantedmem=$(expr $nrcpus '*' 65536)
    machine=$(uname -m)

    # I only deal with two architectures, x86 and ARM. Using 25% of the buffer
    # size ought to be enough for ARM
    if [ $machine != "x86_64" -a $machine != "x86" ];then
	wantedmem=$(expr $wantedmem '/' 4)
    fi

    halfmem=$(expr $memtotal '/' 2)

    if [ $wantedmem -gt $halfmem ];then
	perfmem=$halfmem
    else
	perfmem=$wantedmem
    fi
else
    perfmem=$(expr $bufsize_opt '*' 1024)
fi

case $callgraph_opt in
    "" )
	perf_cmd="$perf_cmd --call-graph=dwarf,$stack_size"
	;;
    "fp" )
	perf_cmd="$perf_cmd --call-graph=fp"
	;;
    "none" )
	;;
esac

perf_cmd="$perf_cmd -m $perfmem""K"

if [ $use_rt = "yes" ];then
    perf_cmd="$perf_cmd -r $rt_priority"
fi

if [ -e $SAMPLE_RATE_PROCFILE ];then
    echo "Setting "$SAMPLE_RATE_PROCFILE" to "$sample_freq_opt
    echo $sample_freq_opt > $SAMPLE_RATE_PROCFILE
fi

if [ "$timeout_opt" != "" ];then
    $perf_cmd&
    pid=$!
    recording_msg
    sleep $timeout_opt
    kill -2 $pid
    timeout_stop_msg
else
    recording_msg
    $perf_cmd
    echo "Press Ctrl-C to stop recording"
fi