194a420b1SStefan Hajnoczi# Trace events for debugging and performance instrumentation 294a420b1SStefan Hajnoczi# 394a420b1SStefan Hajnoczi# This file is processed by the tracetool script during the build. 494a420b1SStefan Hajnoczi# 594a420b1SStefan Hajnoczi# To add a new trace event: 694a420b1SStefan Hajnoczi# 794a420b1SStefan Hajnoczi# 1. Choose a name for the trace event. Declare its arguments and format 894a420b1SStefan Hajnoczi# string. 994a420b1SStefan Hajnoczi# 1094a420b1SStefan Hajnoczi# 2. Call the trace event from code using trace_##name, e.g. multiwrite_cb() -> 1194a420b1SStefan Hajnoczi# trace_multiwrite_cb(). The source file must #include "trace.h". 1294a420b1SStefan Hajnoczi# 1394a420b1SStefan Hajnoczi# Format of a trace event: 1494a420b1SStefan Hajnoczi# 15*1e2cf2bcSStefan Hajnoczi# [disable] <name>(<type1> <arg1>[, <type2> <arg2>] ...) "<format-string>" 1694a420b1SStefan Hajnoczi# 1794a420b1SStefan Hajnoczi# Example: qemu_malloc(size_t size) "size %zu" 1894a420b1SStefan Hajnoczi# 19*1e2cf2bcSStefan Hajnoczi# The "disable" keyword will build without the trace event. 20*1e2cf2bcSStefan Hajnoczi# In case of 'simple' trace backend, it will allow the trace event to be 21*1e2cf2bcSStefan Hajnoczi# compiled, but this would be turned off by default. It can be toggled on via 22*1e2cf2bcSStefan Hajnoczi# the monitor. 23*1e2cf2bcSStefan Hajnoczi# 2494a420b1SStefan Hajnoczi# The <name> must be a valid as a C function name. 2594a420b1SStefan Hajnoczi# 2694a420b1SStefan Hajnoczi# Types should be standard C types. Use void * for pointers because the trace 2794a420b1SStefan Hajnoczi# system may not have the necessary headers included. 2894a420b1SStefan Hajnoczi# 2994a420b1SStefan Hajnoczi# The <format-string> should be a sprintf()-compatible format string. 30