#!/bin/bash
#
# This is example of how to do host and guest tracing. This script
# runs in the guest.
#
# To use this script:
#
# 1. Make sure the guest can access the host via ssh without a
#    password
#
# 2. Edit the Host config and Guest config sections to match
#    you setup
#
# 3. Edit start_host_tracing() and guest_trace_run() to
#    add/remove tracepoints, function filters and etc
#
# 4. Run the trace:
#
#      # trace-host-and-guest < program >
#
# 5. Once the trace is finished, run the following command in
#    the host to merge the traces:
#
#      $ trace-cmd report --ts-diff --ts2secs $HOST_FREQUENCY -t \
#         -i host-trace.dat --ts-offset $(($GUEST_TSC_OFFSET)) \
#         -i guest-trace.dat
#
#   Where $GUEST_TSC_OFFSET is the vCPU TSC offset from
#   /sys/kernel/debug/kvm, and $HOST_FREQUENCY. Here's an example:
#
#      $ trace-cmd report --ts-diff --ts2secs 26000000000 -t \
#         -i host-trace.dat --ts-offset $(($GUEST_TSC_OFFSET)) \
#         -i guest-trace.dat
#
# Luiz Capitulino <lcapitulino@redhat.com>

set -e

# Host config
host_addr=
host_cpu_mask=
host_trace_dir=/root/tracing
host_trace_file=$host_trace_dir/host-trace.dat
host_guest_trace_file=$host_trace_dir/guest-trace.dat
host_trace=trace-cmd

# Guest config
guest_cpu_mask=
guest_trace_file=./trace.dat
guest_trace=trace-cmd

start_host_tracing()
{
	ssh $host_addr $host_trace start \
		-M $host_cpu_mask \
		-p function \
		-C x86-tsc \
		-e kvm_entry \
		-e kvm_exit \
		-e sched_switch \
		-l apic_timer_fn \
		-l kvm_inject_pending_timer_irqs \
		-l kvm_set_lapic_tscdeadline_msr
}

stop_host_tracing()
{
	local outf=$1

	ssh $host_addr $host_trace stop
	ssh $host_addr $host_trace extract -o $outf
}

guest_trace_run()
{
	echo running $*

	$guest_trace record     \
		-M $guest_cpu_mask \
		-p function \
		-C x86-tsc         \
		-e sys_enter_clock_nanosleep \
		-e sys_exit_clock_nanosleep \
		-l smp_apic_timer_interrupt \
		$*
}

copy_guest_trace()
{
	scp $guest_trace_file $host_addr:$host_guest_trace_file
}

if [ "$(id -u)" -ne 0 ]; then
	echo "ERROR: must run as root"
	exit 1
fi

start_host_tracing

guest_trace_run $*

stop_host_tracing $host_trace_file
copy_guest_trace