Commit 4addb112 authored by Daniel P. Berrangé's avatar Daniel P. Berrangé Committed by Anthony Liguori
Browse files

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

Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 96968466

.gitignore

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ config-host.* 
config-target.*

trace.h

trace.c

trace-dtrace.h

trace-dtrace.dtrace

*-timestamp

*-softmmu

*-darwin-user

Makefile

+23 −0
Original line number Diff line number Diff line 
# Makefile for QEMU.



GENERATED_HEADERS = config-host.h trace.h qemu-options.def

ifeq ($(TRACE_BACKEND),dtrace)

GENERATED_HEADERS += trace-dtrace.h

endif



ifneq ($(wildcard config-host.mak),)

# Put the all: rule here so that config-host.mak can contain dependencies.
@@ -108,7 +111,11 @@ ui/vnc.o: QEMU_CFLAGS += $(VNC_TLS_CFLAGS) 


bt-host.o: QEMU_CFLAGS += $(BLUEZ_CFLAGS)



ifeq ($(TRACE_BACKEND),dtrace)

trace.h: trace.h-timestamp trace-dtrace.h

else

trace.h: trace.h-timestamp

endif

trace.h-timestamp: $(SRC_PATH)/trace-events config-host.mak

	$(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -h < $< > $@,"  GEN   trace.h")

	@cmp -s $@ trace.h || cp $@ trace.h
@@ -120,6 +127,20 @@ trace.c-timestamp: $(SRC_PATH)/trace-events config-host.mak 


trace.o: trace.c $(GENERATED_HEADERS)



trace-dtrace.h: trace-dtrace.dtrace

	$(call quiet-command,dtrace -o $@ -h -s $<, "  GEN   trace-dtrace.h")



# Normal practice is to name DTrace probe file with a '.d' extension

# but that gets picked up by QEMU's Makefile as an external dependancy

# rule file. So we use '.dtrace' instead

trace-dtrace.dtrace: trace-dtrace.dtrace-timestamp

trace-dtrace.dtrace-timestamp: $(SRC_PATH)/trace-events config-host.mak

	$(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -d < $< > $@,"  GEN   trace-dtrace.dtrace")

	@cmp -s $@ trace-dtrace.dtrace || cp $@ trace-dtrace.dtrace



trace-dtrace.o: trace-dtrace.dtrace $(GENERATED_HEADERS)

	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN trace-dtrace.o")



simpletrace.o: simpletrace.c $(GENERATED_HEADERS)



version.o: $(SRC_PATH)/version.rc config-host.mak
@@ -157,6 +178,8 @@ clean: 
	rm -f slirp/*.o slirp/*.d audio/*.o audio/*.d block/*.o block/*.d net/*.o net/*.d fsdev/*.o fsdev/*.d ui/*.o ui/*.d

	rm -f qemu-img-cmds.h

	rm -f trace.c trace.h trace.c-timestamp trace.h-timestamp

	rm -f trace-dtrace.dtrace trace-dtrace.dtrace-timestamp

	rm -f trace-dtrace.h trace-dtrace.h-timestamp

	$(MAKE) -C tests clean

	for d in $(ALL_SUBDIRS) libhw32 libhw64 libuser libdis libdis-user; do \

	if test -d $$d; then $(MAKE) -C $$d $@ || exit 1; fi; \

Makefile.objs

+4 −0
Original line number Diff line number Diff line
@@ -286,11 +286,15 @@ libdis-$(CONFIG_SPARC_DIS) += sparc-dis.o 
######################################################################

# trace



ifeq ($(TRACE_BACKEND),dtrace)

trace-obj-y = trace-dtrace.o

else

trace-obj-y = trace.o

ifeq ($(TRACE_BACKEND),simple)

trace-obj-y += simpletrace.o

user-obj-y += qemu-timer-common.o

endif

endif



vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)

configure

+13 −1
Original line number Diff line number Diff line
@@ -929,7 +929,7 @@ echo " --enable-docs enable documentation build" 
echo "  --disable-docs           disable documentation build"

echo "  --disable-vhost-net      disable vhost-net acceleration support"

echo "  --enable-vhost-net       enable vhost-net acceleration support"

echo "  --trace-backend=B        Trace backend nop simple ust"

echo "  --trace-backend=B        Trace backend nop simple ust dtrace"

echo "  --trace-file=NAME        Full PATH,NAME of file to store traces"

echo "                           Default:trace-<pid>"

echo "  --disable-spice          disable spice"
@@ -2193,6 +2193,18 @@ EOF 
    exit 1

  fi

fi



##########################################

# For 'dtrace' backend, test if 'dtrace' command is present

if test "$trace_backend" = "dtrace"; then

  if ! has 'dtrace' ; then

    echo

    echo "Error: dtrace command is not found in PATH $PATH"

    echo

    exit 1

  fi

fi



##########################################

# End of CC checks

# After here, no more $cc or $ld runs

tracetool

+106 −10
Original line number Diff line number Diff line
@@ -20,10 +20,12 @@ Backends: 
  --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_args() 
# 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=$((nfields + 1))
@@ -58,7 +61,7 @@ get_argnames() 
        name=${field%,}

        test "$field" = "$name" && continue



        printf "%s" "$name, "

        printf "%s%s " $name $sep

    done



    # Last argument name
@@ -73,7 +76,7 @@ get_argc() 
{

    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 @@ EOF 
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 @@ linetoh_ust() 
    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 @@ linetoc_ust() 
    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 +309,87 @@ EOF 
    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



    # 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 +408,10 @@ convert() 
        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 +445,19 @@ tracetoc() 
    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 +465,7 @@ shift 
case "$1" in

"-h") tracetoh ;;

"-c") tracetoc ;;

"-d") tracetod ;;

"--check-backend") exit 0 ;; # used by ./configure to test for backend

*) usage ;;

esac