Add a DTrace tracing backend targetted for SystemTAP compatability
This introduces a new tracing backend that targets the SystemTAP
implementation of DTrace userspace tracing. The core functionality
should be applicable and standard across any DTrace implementation
on Solaris, OS-X, *BSD, but the Makefile rules will likely need
some small additional changes to cope with OS specific build
requirements.
This backend builds a little differently from the other tracing
backends. Specifically there is no 'trace.c' file, because the
'dtrace' command line tool generates a '.o' file directly from
the dtrace probe definition file. The probe definition is usually
named with a '.d' extension but QEMU uses '.d' files for its
external makefile dependancy tracking, so this uses '.dtrace' as
the extension for the probe definition file.
The 'tracetool' program gains the ability to generate a trace.h
file for DTrace, and also to generate the trace.d file containing
the dtrace probe definition.
Example usage of a dtrace probe in systemtap looks like:
probe process("qemu").mark("qemu_malloc") {
printf("Malloc %d %p\n", $arg1, $arg2);
}
* .gitignore: Ignore trace-dtrace.*
* Makefile: Extra rules for generating DTrace files
* Makefile.obj: Don't build trace.o for DTrace, use
trace-dtrace.o generated by 'dtrace' instead
* tracetool: Support for generating DTrace data files
Reviewed-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Daniel P. Berrange <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
diff --git a/tracetool b/tracetool
index 7010858..1ade103 100755
--- a/tracetool
+++ b/tracetool
@@ -20,10 +20,12 @@
--nop Tracing disabled
--simple Simple built-in backend
--ust LTTng User Space Tracing backend
+ --dtrace DTrace/SystemTAP backend
Output formats:
-h Generate .h file
-c Generate .c file
+ -d Generate .d file (DTrace only)
EOF
exit 1
}
@@ -46,8 +48,9 @@
# Get the argument name list of a trace event
get_argnames()
{
- local nfields field name
+ local nfields field name sep
nfields=0
+ sep="$2"
for field in $(get_args "$1"); do
nfields=$((nfields + 1))
@@ -58,7 +61,7 @@
name=${field%,}
test "$field" = "$name" && continue
- printf "%s" "$name, "
+ printf "%s%s " $name $sep
done
# Last argument name
@@ -73,7 +76,7 @@
{
local name argc
argc=0
- for name in $(get_argnames "$1"); do
+ for name in $(get_argnames "$1", ","); do
argc=$((argc + 1))
done
echo $argc
@@ -154,7 +157,7 @@
cast_args_to_uint64_t()
{
local arg
- for arg in $(get_argnames "$1"); do
+ for arg in $(get_argnames "$1", ","); do
printf "%s" "(uint64_t)(uintptr_t)$arg"
done
}
@@ -247,7 +250,7 @@
local name args argnames
name=$(get_name "$1")
args=$(get_args "$1")
- argnames=$(get_argnames "$1")
+ argnames=$(get_argnames "$1", ",")
cat <<EOF
DECLARE_TRACE(ust_$name, TP_PROTO($args), TP_ARGS($argnames));
@@ -274,7 +277,7 @@
local name args argnames fmt
name=$(get_name "$1")
args=$(get_args "$1")
- argnames=$(get_argnames "$1")
+ argnames=$(get_argnames "$1", ",")
fmt=$(get_fmt "$1")
cat <<EOF
@@ -306,6 +309,93 @@
echo "}"
}
+linetoh_begin_dtrace()
+{
+ cat <<EOF
+#include "trace-dtrace.h"
+EOF
+}
+
+linetoh_dtrace()
+{
+ local name args argnames state nameupper
+ name=$(get_name "$1")
+ args=$(get_args "$1")
+ argnames=$(get_argnames "$1", ",")
+ state=$(get_state "$1")
+ if [ "$state" = "0" ] ; then
+ name=${name##disable }
+ fi
+
+ nameupper=`echo $name | tr '[:lower:]' '[:upper:]'`
+
+ # Define an empty function for the trace event
+ cat <<EOF
+static inline void trace_$name($args) {
+ if (QEMU_${nameupper}_ENABLED()) {
+ QEMU_${nameupper}($argnames);
+ }
+}
+EOF
+}
+
+linetoh_end_dtrace()
+{
+ return
+}
+
+linetoc_begin_dtrace()
+{
+ return
+}
+
+linetoc_dtrace()
+{
+ # No need for function definitions in dtrace backend
+ return
+}
+
+linetoc_end_dtrace()
+{
+ return
+}
+
+linetod_begin_dtrace()
+{
+ cat <<EOF
+provider qemu {
+EOF
+}
+
+linetod_dtrace()
+{
+ local name args state
+ name=$(get_name "$1")
+ args=$(get_args "$1")
+ state=$(get_state "$1")
+ if [ "$state" = "0" ] ; then
+ name=${name##disable }
+ fi
+
+ # DTrace provider syntax expects foo() for empty
+ # params, not foo(void)
+ if [ "$args" = "void" ]; then
+ args=""
+ fi
+
+ # Define prototype for probe arguments
+ cat <<EOF
+ probe $name($args);
+EOF
+}
+
+linetod_end_dtrace()
+{
+ cat <<EOF
+};
+EOF
+}
+
# Process stdin by calling begin, line, and end functions for the backend
convert()
{
@@ -324,9 +414,10 @@
disable=${str%%disable *}
echo
if test -z "$disable"; then
- # Pass the disabled state as an arg to lineto$1_simple().
- # For all other cases, call lineto$1_nop()
- if [ $backend = "simple" ]; then
+ # Pass the disabled state as an arg for the simple
+ # or DTrace backends which handle it dynamically.
+ # For all other backends, call lineto$1_nop()
+ if [ $backend = "simple" -o "$backend" = "dtrace" ]; then
"$process_line" "$str"
else
"lineto$1_nop" "${str##disable }"
@@ -360,9 +451,19 @@
convert c
}
+tracetod()
+{
+ if [ $backend != "dtrace" ]; then
+ echo "DTrace probe generator not applicable to $backend backend"
+ exit 1
+ fi
+ echo "/* This file is autogenerated by tracetool, do not edit. */"
+ convert d
+}
+
# Choose backend
case "$1" in
-"--nop" | "--simple" | "--ust") backend="${1#--}" ;;
+"--nop" | "--simple" | "--ust" | "--dtrace") backend="${1#--}" ;;
*) usage ;;
esac
shift
@@ -370,6 +471,7 @@
case "$1" in
"-h") tracetoh ;;
"-c") tracetoc ;;
+"-d") tracetod ;;
"--check-backend") exit 0 ;; # used by ./configure to test for backend
*) usage ;;
esac
