[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v3 ] trace: Multi-backend tracing
|
From: |
Lluís Vilanova |
|
Subject: |
Re: [Qemu-devel] [PATCH v3 ] trace: Multi-backend tracing |
|
Date: |
Fri, 09 May 2014 16:57:50 +0200 |
|
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Lluís Vilanova writes:
> Adds support to compile QEMU with multiple tracing backends at the same time.
> For example, you can compile QEMU with:
> $ ./configure --enable-trace-backends=ftrace,dtrace
> Where 'ftrace' can be handy for having an in-flight record of events, and
> 'dtrace' can be later used to extract more information from the system.
> This patch allows having both available without recompiling QEMU.
> Signed-off-by: Lluís Vilanova <address@hidden>
> ---
Changes in v3:
* Rebase on 43cbeff.
Changes in v2:
* Rebase on 3e890c7.
* Update ".travis.yml".
* Replace all uses of "TRACE_BACKEND" for "TRACE_BACKENDS".
* Replace "--backend" for "--backends" in "scripts/tracetool.py".
* Update "configure" help and "docs/tracing.txt".
Lluis
> .travis.yml | 8 +++--
> Makefile | 4 +--
> Makefile.target | 4 +--
> configure | 44 +++++++++++++-----------------
> docs/tracing.txt | 4 +--
> qemu-io.c | 2 +
> scripts/tracetool.py | 41 ++++++++++++++--------------
> scripts/tracetool/__init__.py | 22 +++++++--------
> scripts/tracetool/backend/__init__.py | 15 +++++-----
> trace/Makefile.objs | 22 +++++++--------
> trace/control-internal.h | 4 +--
> trace/control.c | 49
> ++++++++++++++++++++++++++++++++-
> trace/control.h | 27 +++---------------
> trace/default.c | 40 ---------------------------
> trace/ftrace.c | 25 +----------------
> trace/ftrace.h | 5 +++
> trace/simple.c | 19 +------------
> trace/simple.h | 1 +
> trace/stderr.c | 30 --------------------
> vl.c | 4 +--
> 20 files changed, 144 insertions(+), 226 deletions(-)
> delete mode 100644 trace/default.c
> delete mode 100644 trace/stderr.c
> diff --git a/.travis.yml b/.travis.yml
> index 04da973..89c30ae 100644
> --- a/.travis.yml
> +++ b/.travis.yml
> @@ -66,16 +66,16 @@ matrix:
> compiler: gcc
> # All the trace backends (apart from dtrace)
> - env: TARGETS=i386-softmmu,x86_64-softmmu
> - EXTRA_CONFIG="--enable-trace-backend=stderr"
> + EXTRA_CONFIG="--enable-trace-backends=stderr"
> compiler: gcc
> - env: TARGETS=i386-softmmu,x86_64-softmmu
> - EXTRA_CONFIG="--enable-trace-backend=simple"
> + EXTRA_CONFIG="--enable-trace-backends=simple"
> compiler: gcc
> - env: TARGETS=i386-softmmu,x86_64-softmmu
> - EXTRA_CONFIG="--enable-trace-backend=ftrace"
> + EXTRA_CONFIG="--enable-trace-backends=ftrace"
> TEST_CMD=""
> compiler: gcc
> - env: TARGETS=i386-softmmu,x86_64-softmmu
> EXTRA_PKGS="liblttng-ust-dev liburcu-dev"
> - EXTRA_CONFIG="--enable-trace-backend=ust"
> + EXTRA_CONFIG="--enable-trace-backends=ust"
> compiler: gcc
> diff --git a/Makefile b/Makefile
> index a120aab..609bf69 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -52,12 +52,12 @@ GENERATED_HEADERS += trace/generated-events.h
> GENERATED_SOURCES += trace/generated-events.c
> GENERATED_HEADERS += trace/generated-tracers.h
> -ifeq ($(TRACE_BACKEND),dtrace)
> +ifeq ($(findstring dtrace,$(TRACE_BACKENDS)),dtrace)
> GENERATED_HEADERS += trace/generated-tracers-dtrace.h
> endif
> GENERATED_SOURCES += trace/generated-tracers.c
> -ifeq ($(TRACE_BACKEND),ust)
> +ifeq ($(findstring ust,$(TRACE_BACKENDS)),ust)
> GENERATED_HEADERS += trace/generated-ust-provider.h
> GENERATED_SOURCES += trace/generated-ust.c
> endif
> diff --git a/Makefile.target b/Makefile.target
> index 6d8fde8..749b2e1 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -46,7 +46,7 @@ endif
> $(QEMU_PROG).stp-installed: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=stap \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> --binary=$(bindir)/$(QEMU_PROG) \
> --target-name=$(TARGET_NAME) \
> --target-type=$(TARGET_TYPE) \
> @@ -55,7 +55,7 @@ $(QEMU_PROG).stp-installed: $(SRC_PATH)/trace-events
> $(QEMU_PROG).stp: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=stap \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> --binary=$(realpath .)/$(QEMU_PROG) \
> --target-name=$(TARGET_NAME) \
> --target-type=$(TARGET_TYPE) \
> diff --git a/configure b/configure
> index 46bc0c9..73b6539 100755
> --- a/configure
> +++ b/configure
> @@ -180,6 +180,10 @@ path_of() {
> return 1
> }
> +have_backend () {
> + echo "$trace_backends" | grep "$1" >/dev/null
> +}
> +
> # default parameters
> source_path=`dirname "$0"`
> cpu=""
> @@ -291,7 +295,7 @@ pkgversion=""
> pie=""
> zero_malloc=""
> qom_cast_debug="yes"
> -trace_backend="nop"
> +trace_backends="nop"
> trace_file="trace"
> spice=""
> rbd=""
> @@ -751,7 +755,7 @@ for opt do
> ;;
> --target-list=*) target_list="$optarg"
> ;;
> - --enable-trace-backend=*) trace_backend="$optarg"
> + --enable-trace-backends=*) trace_backends="$optarg"
> ;;
> --with-trace-file=*) trace_file="$optarg"
> ;;
> @@ -1318,7 +1322,7 @@ Advanced options (experts only):
> --disable-docs disable documentation build
> --disable-vhost-net disable vhost-net acceleration support
> --enable-vhost-net enable vhost-net acceleration support
> - --enable-trace-backend=B Set trace backend
> + --enable-trace-backends=B Set trace backend
> Available backends: $($python
> $source_path/scripts/tracetool.py --list-backends)
> --with-trace-file=NAME Full PATH,NAME of file to store traces
> Default:trace-<pid>
> @@ -3651,15 +3655,15 @@ fi
> ##########################################
> # check if trace backend exists
> -$python "$source_path/scripts/tracetool.py" "--backend=$trace_backend"
> --check-backend > /dev/null 2> /dev/null
> +$python "$source_path/scripts/tracetool.py" "--backends=$trace_backends"
> --check-backends > /dev/null 2> /dev/null
> if test "$?" -ne 0 ; then
> - error_exit "invalid trace backend" \
> - "Please choose a supported trace backend."
> + error_exit "invalid trace backends" \
> + "Please choose supported trace backends."
> fi
> ##########################################
> # For 'ust' backend, test if ust headers are present
> -if test "$trace_backend" = "ust"; then
> +if have_backend "ust"; then
> cat > $TMPC << EOF
> #include <lttng/tracepoint.h>
> int main(void) { return 0; }
> @@ -3685,7 +3689,7 @@ fi
> ##########################################
> # For 'dtrace' backend, test if 'dtrace' command is present
> -if test "$trace_backend" = "dtrace"; then
> +if have_backend "dtrace"; then
> if ! has 'dtrace' ; then
> error_exit "dtrace command is not found in PATH $PATH"
> fi
> @@ -4152,7 +4156,7 @@ echo "uuid support $uuid"
> echo "libcap-ng support $cap_ng"
> echo "vhost-net support $vhost_net"
> echo "vhost-scsi support $vhost_scsi"
> -echo "Trace backend $trace_backend"
> +echo "Trace backends $trace_backends"
> if test "$trace_backend" = "simple"; then
> echo "Trace output file $trace_file-<pid>"
> fi
> @@ -4646,43 +4650,35 @@ if test "$tpm" = "yes"; then
> fi
> fi
> -# use default implementation for tracing backend-specific routines
> -trace_default=yes
> -echo "TRACE_BACKEND=$trace_backend" >> $config_host_mak
> -if test "$trace_backend" = "nop"; then
> +echo "TRACE_BACKENDS=$trace_backends" >> $config_host_mak
> +if have_backend "nop"; then
> echo "CONFIG_TRACE_NOP=y" >> $config_host_mak
> fi
> -if test "$trace_backend" = "simple"; then
> +if have_backend "simple"; then
> echo "CONFIG_TRACE_SIMPLE=y" >> $config_host_mak
> - trace_default=no
> # Set the appropriate trace file.
> trace_file="\"$trace_file-\" FMT_pid"
> fi
> -if test "$trace_backend" = "stderr"; then
> +if have_backend "stderr"; then
> echo "CONFIG_TRACE_STDERR=y" >> $config_host_mak
> - trace_default=no
> fi
> -if test "$trace_backend" = "ust"; then
> +if have_backend "ust"; then
> echo "CONFIG_TRACE_UST=y" >> $config_host_mak
> fi
> -if test "$trace_backend" = "dtrace"; then
> +if have_backend "dtrace"; then
> echo "CONFIG_TRACE_DTRACE=y" >> $config_host_mak
> if test "$trace_backend_stap" = "yes" ; then
> echo "CONFIG_TRACE_SYSTEMTAP=y" >> $config_host_mak
> fi
> fi
> -if test "$trace_backend" = "ftrace"; then
> +if have_backend "ftrace"; then
> if test "$linux" = "yes" ; then
> echo "CONFIG_TRACE_FTRACE=y" >> $config_host_mak
> - trace_default=no
> else
> feature_not_found "ftrace(trace backend)" "ftrace requires Linux"
> fi
> fi
> echo "CONFIG_TRACE_FILE=$trace_file" >> $config_host_mak
> -if test "$trace_default" = "yes"; then
> - echo "CONFIG_TRACE_DEFAULT=y" >> $config_host_mak
> -fi
> if test "$rdma" = "yes" ; then
> echo "CONFIG_RDMA=y" >> $config_host_mak
> diff --git a/docs/tracing.txt b/docs/tracing.txt
> index bf2e15c..c6ab1c1 100644
> --- a/docs/tracing.txt
> +++ b/docs/tracing.txt
> @@ -9,7 +9,7 @@ for debugging, profiling, and observing execution.
> 1. Build with the 'simple' trace backend:
> - ./configure --enable-trace-backend=simple
> + ./configure --enable-trace-backends=simple
> make
> 2. Create a file with the events you want to trace:
> @@ -142,7 +142,7 @@ script.
> The trace backend is chosen at configure time and only one trace backend can
> be built into the binary:
> - ./configure --trace-backend=simple
> + ./configure --trace-backends=simple
> For a list of supported trace backends, try ./configure --help or see below.
> diff --git a/qemu-io.c b/qemu-io.c
> index 9fcd72b..6b84b93 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -425,7 +425,7 @@ int main(int argc, char **argv)
> }
> break;
> case 'T':
> - if (!trace_backend_init(optarg, NULL)) {
> + if (!trace_init_backends(optarg, NULL)) {
> exit(1); /* error message will have been printed */
> }
> break;
> diff --git a/scripts/tracetool.py b/scripts/tracetool.py
> index 5f4890f..59c4810 100755
> --- a/scripts/tracetool.py
> +++ b/scripts/tracetool.py
> @@ -6,7 +6,7 @@ Command-line wrapper for the tracetool machinery.
> """
> __author__ = "Lluís Vilanova <address@hidden>"
> -__copyright__ = "Copyright 2012, Lluís Vilanova <address@hidden>"
> +__copyright__ = "Copyright 2012-2014, Lluís Vilanova <address@hidden>"
> __license__ = "GPL version 2 or (at your option) any later version"
> __maintainer__ = "Stefan Hajnoczi"
> @@ -32,7 +32,7 @@ def error_opt(msg = None):
> format_descr = "\n".join([ " %-15s %s" % (n, d)
> for n,d in tracetool.format.get_list() ])
> error_write("""\
> -Usage: %(script)s --format=<format> --backend=<backend> [<options>]
> +Usage: %(script)s --format=<format> --backends=<backends> [<options>]
> Backends:
> %(backends)s
> @@ -65,16 +65,17 @@ def main(args):
> global _SCRIPT
> _SCRIPT = args[0]
> - long_opts = [ "backend=", "format=", "help", "list-backends",
> "check-backend" ]
> - long_opts += [ "binary=", "target-type=", "target-name=",
> "probe-prefix=" ]
> + long_opts = ["backends=", "format=", "help", "list-backends",
> + "check-backends"]
> + long_opts += ["binary=", "target-type=", "target-name=", "probe-prefix="]
> try:
> opts, args = getopt.getopt(args[1:], "", long_opts)
> except getopt.GetoptError, err:
> error_opt(str(err))
> - check_backend = False
> - arg_backend = ""
> + check_backends = False
> + arg_backends = []
> arg_format = ""
> binary = None
> target_type = None
> @@ -84,8 +85,8 @@ def main(args):
> if opt == "--help":
> error_opt()
> - elif opt == "--backend":
> - arg_backend = arg
> + elif opt == "--backends":
> + arg_backends = arg.split(",")
> elif opt == "--format":
> arg_format = arg
> @@ -93,8 +94,8 @@ def main(args):
> public_backends = tracetool.backend.get_list(only_public = True)
> out(", ".join([ b for b,_ in public_backends ]))
> sys.exit(0)
> - elif opt == "--check-backend":
> - check_backend = True
> + elif opt == "--check-backends":
> + check_backends = True
> elif opt == "--binary":
> binary = arg
> @@ -108,14 +109,14 @@ def main(args):
> else:
> error_opt("unhandled option: %s" % opt)
> - if arg_backend is None:
> - error_opt("backend not set")
> + if len(arg_backends) == 0:
> + error_opt("no backends specified")
> - if check_backend:
> - if tracetool.backend.exists(arg_backend):
> - sys.exit(0)
> - else:
> - sys.exit(1)
> + if check_backends:
> + for backend in arg_backends:
> + if not tracetool.backend.exists(backend):
> + sys.exit(1)
> + sys.exit(0)
> if arg_format == "stap":
> if binary is None:
> @@ -126,11 +127,11 @@ def main(args):
> error_opt("--target-name is required for SystemTAP tapset
> generator")
> if probe_prefix is None:
> - probe_prefix = ".".join([ "qemu", target_type, target_name ])
> + probe_prefix = ".".join(["qemu", target_type, target_name])
> try:
> - tracetool.generate(sys.stdin, arg_format, arg_backend,
> - binary = binary, probe_prefix = probe_prefix)
> + tracetool.generate(sys.stdin, arg_format, arg_backends,
> + binary=binary, probe_prefix=probe_prefix)
> except tracetool.TracetoolError, e:
> error_opt(str(e))
> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
> index eccf552..5cc73ac 100644
> --- a/scripts/tracetool/__init__.py
> +++ b/scripts/tracetool/__init__.py
> @@ -233,9 +233,9 @@ def try_import(mod_name, attr_name=None,
> attr_default=None):
> return False, None
> -def generate(fevents, format, backend,
> +def generate(fevents, format, backends,
> binary=None, probe_prefix=None):
> - """Generate the output for the given (format, backend) pair.
> + """Generate the output for the given (format, backends) pair.
> Parameters
> ----------
> @@ -243,8 +243,8 @@ def generate(fevents, format, backend,
> Event description file.
> format : str
> Output format name.
> - backend : str
> - Output backend name.
> + backends : list
> + Output backend names.
> binary : str or None
> See tracetool.backend.dtrace.BINARY.
> probe_prefix : str or None
> @@ -260,13 +260,13 @@ def generate(fevents, format, backend,
> raise TracetoolError("unknown format: %s" % format)
> format = format.replace("-", "_")
> - backend = str(backend)
> - if len(backend) is 0:
> - raise TracetoolError("backend not set")
> - if not tracetool.backend.exists(backend):
> - raise TracetoolError("unknown backend: %s" % backend)
> - backend = backend.replace("-", "_")
> - backend = tracetool.backend.Wrapper(backend, format)
> + if len(backends) is 0:
> + raise TracetoolError("no backends specified")
> + for backend in backends:
> + if not tracetool.backend.exists(backend):
> + raise TracetoolError("unknown backend: %s" % backend)
> + backends = [backend.replace("-", "_") for backend in backends]
> + backend = tracetool.backend.Wrapper(backends, format)
> import tracetool.backend.dtrace
> tracetool.backend.dtrace.BINARY = binary
> diff --git a/scripts/tracetool/backend/__init__.py
> b/scripts/tracetool/backend/__init__.py
> index 5e36f04..5bfa1ef 100644
> --- a/scripts/tracetool/backend/__init__.py
> +++ b/scripts/tracetool/backend/__init__.py
> @@ -99,17 +99,18 @@ def exists(name):
> class Wrapper:
> - def __init__(self, backend, format):
> - self._backend = backend.replace("-", "_")
> + def __init__(self, backends, format):
> + self._backends = [backend.replace("-", "_") for backend in backends]
> self._format = format.replace("-", "_")
> - assert exists(self._backend)
> + assert all(exists(backend) for backend in self._backends)
> assert tracetool.format.exists(self._format)
> def _run_function(self, name, *args, **kwargs):
> - func = tracetool.try_import("tracetool.backend." + self._backend,
> - name % self._format, None)[1]
> - if func is not None:
> - func(*args, **kwargs)
> + for backend in self._backends:
> + func = tracetool.try_import("tracetool.backend." + backend,
> + name % self._format, None)[1]
> + if func is not None:
> + func(*args, **kwargs)
> def generate_begin(self, events):
> self._run_function("generate_%s_begin", events)
> diff --git a/trace/Makefile.objs b/trace/Makefile.objs
> index 6a30467..e4aa45c 100644
> --- a/trace/Makefile.objs
> +++ b/trace/Makefile.objs
> @@ -3,12 +3,12 @@
> ######################################################################
> # Auto-generated event descriptions for LTTng ust code
> -ifeq ($(TRACE_BACKEND),ust)
> +ifeq ($(findstring ust,$(TRACE_BACKENDS)),ust)
> $(obj)/generated-ust-provider.h: $(obj)/generated-ust-provider.h-timestamp
> $(obj)/generated-ust-provider.h-timestamp: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=ust-events-h \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst
> %-timestamp,%,$@)
> @@ -16,7 +16,7 @@ $(obj)/generated-ust.c: $(obj)/generated-ust.c-timestamp
> $(BUILD_DIR)/config-hos
> $(obj)/generated-ust.c-timestamp: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=ust-events-c \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst
> %-timestamp,%,$@)
> @@ -31,7 +31,7 @@ $(obj)/generated-events.h:
> $(obj)/generated-events.h-timestamp
> $(obj)/generated-events.h-timestamp: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=events-h \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst
> %-timestamp,%,$@)
> @@ -39,7 +39,7 @@ $(obj)/generated-events.c:
> $(obj)/generated-events.c-timestamp $(BUILD_DIR)/conf
> $(obj)/generated-events.c-timestamp: $(SRC_PATH)/trace-events
> $(call quiet-command,$(TRACETOOL) \
> --format=events-c \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst
> %-timestamp,%,$@)
> @@ -54,19 +54,19 @@ $(obj)/generated-tracers.h:
> $(obj)/generated-tracers.h-timestamp
> $(obj)/generated-tracers.h-timestamp: $(SRC_PATH)/trace-events
> $(BUILD_DIR)/config-host.mak
> $(call quiet-command,$(TRACETOOL) \
> --format=h \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> ######################################################################
> # Auto-generated tracing routines (non-DTrace)
> -ifneq ($(TRACE_BACKEND),dtrace)
> +ifneq ($(findstring dtrace,$(TRACE_BACKENDS)),dtrace)
> $(obj)/generated-tracers.c: $(obj)/generated-tracers.c-timestamp
> @cmp -s $< $@ || cp $< $@
> $(obj)/generated-tracers.c-timestamp: $(SRC_PATH)/trace-events
> $(BUILD_DIR)/config-host.mak
> $(call quiet-command,$(TRACETOOL) \
> --format=c \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> $(obj)/generated-tracers.o: $(obj)/generated-tracers.c
> $(obj)/generated-tracers.h
> @@ -79,12 +79,12 @@ endif
> # Normal practice is to name DTrace probe file with a '.d' extension
> # but that gets picked up by QEMU's Makefile as an external dependency
> # rule file. So we use '.dtrace' instead
> -ifeq ($(TRACE_BACKEND),dtrace)
> +ifeq ($(findstring dtrace,$(TRACE_BACKENDS)),dtrace)
> $(obj)/generated-tracers.dtrace: $(obj)/generated-tracers.dtrace-timestamp
> $(obj)/generated-tracers.dtrace-timestamp: $(SRC_PATH)/trace-events
> $(BUILD_DIR)/config-host.mak
> $(call quiet-command,$(TRACETOOL) \
> --format=d \
> - --backend=$(TRACE_BACKEND) \
> + --backends=$(TRACE_BACKENDS) \
> < $< > $@," GEN $(patsubst %-timestamp,%,$@)")
> @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst
> %-timestamp,%,$@)
> @@ -97,9 +97,7 @@ endif
> ######################################################################
> # Backend code
> -util-obj-$(CONFIG_TRACE_DEFAULT) += default.o
> util-obj-$(CONFIG_TRACE_SIMPLE) += simple.o
> -util-obj-$(CONFIG_TRACE_STDERR) += stderr.o
> util-obj-$(CONFIG_TRACE_FTRACE) += ftrace.o
> util-obj-$(CONFIG_TRACE_UST) += generated-ust.o
> util-obj-y += control.o
> diff --git a/trace/control-internal.h b/trace/control-internal.h
> index b3f587e..5a8df28 100644
> --- a/trace/control-internal.h
> +++ b/trace/control-internal.h
> @@ -1,7 +1,7 @@
> /*
> * Interface for configuring and controlling the state of tracing events.
> *
> - * Copyright (C) 2011-2012 Lluís Vilanova <address@hidden>
> + * Copyright (C) 2011-2014 Lluís Vilanova <address@hidden>
> *
> * This work is licensed under the terms of the GNU GPL, version 2 or later.
> * See the COPYING file in the top-level directory.
> @@ -61,7 +61,7 @@ static inline void trace_event_set_state_dynamic(TraceEvent
> *ev, bool state)
> {
> assert(ev != NULL);
> assert(trace_event_get_state_static(ev));
> - return trace_event_set_state_dynamic_backend(ev, state);
> + ev->dstate = state;
> }
> #endif /* TRACE__CONTROL_INTERNAL_H */
> diff --git a/trace/control.c b/trace/control.c
> index 49f61e1..09c345c 100644
> --- a/trace/control.c
> +++ b/trace/control.c
> @@ -1,13 +1,19 @@
> /*
> * Interface for configuring and controlling the state of tracing events.
> *
> - * Copyright (C) 2011-2012 Lluís Vilanova <address@hidden>
> + * Copyright (C) 2011-2014 Lluís Vilanova <address@hidden>
> *
> * This work is licensed under the terms of the GNU GPL, version 2 or later.
> * See the COPYING file in the top-level directory.
> */
> #include "trace/control.h"
> +#ifdef CONFIG_TRACE_SIMPLE
> +#include "trace/simple.h"
> +#endif
> +#ifdef CONFIG_TRACE_FTRACE
> +#include "trace/ftrace.h"
> +#endif
> TraceEvent *trace_event_name(const char *name)
> @@ -79,7 +85,20 @@ TraceEvent *trace_event_pattern(const char *pat,
> TraceEvent *ev)
> return NULL;
> }
> -void trace_backend_init_events(const char *fname)
> +void trace_print_events(FILE *stream, fprintf_function stream_printf)
> +{
> + TraceEventID i;
> +
> + for (i = 0; i < trace_event_count(); i++) {
> + TraceEvent *ev = trace_event_id(i);
> + stream_printf(stream, "%s [Event ID %u] : state %u\n",
> + trace_event_get_name(ev), i,
> + trace_event_get_state_static(ev) &&
> + trace_event_get_state_dynamic(ev));
> + }
> +}
> +
> +static void trace_init_events(const char *fname)
> {
> if (fname == NULL) {
> return;
> @@ -130,3 +149,29 @@ void trace_backend_init_events(const char *fname)
> exit(1);
> }
> }
> +
> +bool trace_init_backends(const char *events, const char *file)
> +{
> +#ifdef CONFIG_TRACE_SIMPLE
> + if (!st_init(file)) {
> + fprintf(stderr, "failed to initialize simple tracing
> backend.\n");
> + return false;
> + }
> +#else
> + if (file) {
> + fprintf(stderr, "error: -trace file=...: "
> + "option not supported by the selected tracing backends\n");
> + return false;
> + }
> +#endif
> +
> +#ifdef CONFIG_TRACE_FTRACE
> + if (!ftrace_init()) {
> + fprintf(stderr, "failed to initialize ftrace backend.\n");
> + return false;
> + }
> +#endif
> +
> + trace_init_events(events);
> + return true;
> +}
> diff --git a/trace/control.h b/trace/control.h
> index cde8260..e1ec033 100644
> --- a/trace/control.h
> +++ b/trace/control.h
> @@ -1,7 +1,7 @@
> /*
> * Interface for configuring and controlling the state of tracing events.
> *
> - * Copyright (C) 2011-2012 Lluís Vilanova <address@hidden>
> + * Copyright (C) 2011-2014 Lluís Vilanova <address@hidden>
> *
> * This work is licensed under the terms of the GNU GPL, version 2 or later.
> * See the COPYING file in the top-level directory.
> @@ -146,26 +146,17 @@ static bool trace_event_get_state_dynamic(TraceEvent
> *ev);
> */
> static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
> -/**
> - * trace_event_set_state_dynamic_backend:
> - *
> - * Warning: This function must be implemented by each tracing backend.
> - */
> -void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state);
> -
> /**
> * trace_print_events:
> *
> * Print the state of all events.
> - *
> - * Warning: This function must be implemented by each tracing backend.
> */
> void trace_print_events(FILE *stream, fprintf_function stream_printf);
> /**
> - * trace_backend_init:
> + * trace_init_backends:
> * @events: Name of file with events to be enabled at startup; may be NULL.
> * Corresponds to commandline option "-trace events=...".
> * @file: Name of trace output file; may be NULL.
> @@ -173,19 +164,9 @@ void trace_print_events(FILE *stream, fprintf_function
> stream_printf);
> *
> * Initialize the tracing backend.
> *
> - * Warning: This function must be implemented by each tracing backend.
> - *
> - * Returns: Whether the backend could be successfully initialized.
> - */
> -bool trace_backend_init(const char *events, const char *file);
> -
> -/**
> - * trace_backend_init_events:
> - * @fname: Name of file with events to enable; may be NULL.
> - *
> - * Generic function to initialize the state of events.
> + * Returns: Whether the backends could be successfully initialized.
> */
> -void trace_backend_init_events(const char *fname);
> +bool trace_init_backends(const char *events, const char *file);
> #include "trace/control-internal.h"
> diff --git a/trace/default.c b/trace/default.c
> deleted file mode 100644
> index 6e07a47..0000000
> --- a/trace/default.c
> +++ /dev/null
> @@ -1,40 +0,0 @@
> -/*
> - * Default implementation for backend initialization from commandline.
> - *
> - * Copyright (C) 2011-2012 Lluís Vilanova <address@hidden>
> - *
> - * This work is licensed under the terms of the GNU GPL, version 2. See
> - * the COPYING file in the top-level directory.
> - */
> -
> -#include "trace/control.h"
> -
> -
> -void trace_print_events(FILE *stream, fprintf_function stream_printf)
> -{
> - fprintf(stderr, "warning: "
> - "cannot print the trace events with the current backend\n");
> - stream_printf(stream, "error: "
> - "operation not supported with the current backend\n");
> -}
> -
> -void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
> -{
> - fprintf(stderr, "warning: "
> - "cannot set the state of a trace event with the current
> backend\n");
> -}
> -
> -bool trace_backend_init(const char *events, const char *file)
> -{
> - if (events) {
> - fprintf(stderr, "error: -trace events=...: "
> - "option not supported by the selected tracing backend\n");
> - return false;
> - }
> - if (file) {
> - fprintf(stderr, "error: -trace file=...: "
> - "option not supported by the selected tracing backend\n");
> - return false;
> - }
> - return true;
> -}
> diff --git a/trace/ftrace.c b/trace/ftrace.c
> index 46b7fdb..a7ae371 100644
> --- a/trace/ftrace.c
> +++ b/trace/ftrace.c
> @@ -42,35 +42,13 @@ static int find_debugfs(char *debugfs)
> return 1;
> }
> -void trace_print_events(FILE *stream, fprintf_function stream_printf)
> -{
> - TraceEventID i;
> -
> - for (i = 0; i < trace_event_count(); i++) {
> - TraceEvent *ev = trace_event_id(i);
> - stream_printf(stream, "%s [Event ID %u] : state %u\n",
> - trace_event_get_name(ev), i,
> trace_event_get_state_dynamic(ev));
> - }
> -}
> -
> -void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
> -{
> - ev->dstate = state;
> -}
> -
> -bool trace_backend_init(const char *events, const char *file)
> +bool ftrace_init(void)
> {
> char debugfs[PATH_MAX];
> char path[PATH_MAX];
> int debugfs_found;
> int trace_fd = -1;
> - if (file) {
> - fprintf(stderr, "error: -trace file=...: "
> - "option not supported by the selected tracing backend\n");
> - return false;
> - }
> -
> debugfs_found = find_debugfs(debugfs);
> if (debugfs_found) {
> snprintf(path, PATH_MAX, "%s/tracing/tracing_on", debugfs);
> @@ -97,6 +75,5 @@ bool trace_backend_init(const char *events, const char
> *file)
> return false;
> }
> - trace_backend_init_events(events);
> return true;
> }
> diff --git a/trace/ftrace.h b/trace/ftrace.h
> index 94cb8d5..ad18ccb 100644
> --- a/trace/ftrace.h
> +++ b/trace/ftrace.h
> @@ -1,10 +1,15 @@
> #ifndef TRACE_FTRACE_H
> #define TRACE_FTRACE_H
> +#include <stdint.h>
> +
> +
> #define MAX_TRACE_STRLEN 512
> #define _STR(x) #x
> #define STR(x) _STR(x)
> extern int trace_marker_fd;
> +bool ftrace_init(void);
> +
> #endif /* ! TRACE_FTRACE_H */
> diff --git a/trace/simple.c b/trace/simple.c
> index bb0b52c..67e16e8 100644
> --- a/trace/simple.c
> +++ b/trace/simple.c
> @@ -366,22 +366,6 @@ void st_flush_trace_buffer(void)
> flush_trace_file(true);
> }
> -void trace_print_events(FILE *stream, fprintf_function stream_printf)
> -{
> - unsigned int i;
> -
> - for (i = 0; i < trace_event_count(); i++) {
> - TraceEvent *ev = trace_event_id(i);
> - stream_printf(stream, "%s [Event ID %u] : state %u\n",
> - trace_event_get_name(ev), i,
> trace_event_get_state_dynamic(ev));
> - }
> -}
> -
> -void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
> -{
> - ev->dstate = state;
> -}
> -
> /* Helper function to create a thread with signals blocked. Use glib's
> * portable threads since QEMU abstractions cannot be used due to reentrancy
> in
> * the tracer. Also note the signal masking on POSIX hosts so that the
> thread
> @@ -410,7 +394,7 @@ static GThread *trace_thread_create(GThreadFunc fn)
> return thread;
> }
> -bool trace_backend_init(const char *events, const char *file)
> +bool st_init(const char *file)
> {
> GThread *thread;
> @@ -426,7 +410,6 @@ bool trace_backend_init(const char *events, const char
> *file)
> }
> atexit(st_flush_trace_buffer);
> - trace_backend_init_events(events);
> st_set_trace_file(file);
> return true;
> }
> diff --git a/trace/simple.h b/trace/simple.h
> index 5260d9a..6997996 100644
> --- a/trace/simple.h
> +++ b/trace/simple.h
> @@ -21,6 +21,7 @@
> void st_print_trace_file_status(FILE *stream, fprintf_function
> stream_printf);
> void st_set_trace_file_enabled(bool enable);
> bool st_set_trace_file(const char *file);
> +bool st_init(const char *file);
> void st_flush_trace_buffer(void);
> typedef struct {
> diff --git a/trace/stderr.c b/trace/stderr.c
> deleted file mode 100644
> index e212efd..0000000
> --- a/trace/stderr.c
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -#include "trace.h"
> -#include "trace/control.h"
> -
> -
> -void trace_print_events(FILE *stream, fprintf_function stream_printf)
> -{
> - TraceEventID i;
> -
> - for (i = 0; i < trace_event_count(); i++) {
> - TraceEvent *ev = trace_event_id(i);
> - stream_printf(stream, "%s [Event ID %u] : state %u\n",
> - trace_event_get_name(ev), i,
> trace_event_get_state_dynamic(ev));
> - }
> -}
> -
> -void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
> -{
> - ev->dstate = state;
> -}
> -
> -bool trace_backend_init(const char *events, const char *file)
> -{
> - if (file) {
> - fprintf(stderr, "error: -trace file=...: "
> - "option not supported by the selected tracing backend\n");
> - return false;
> - }
> - trace_backend_init_events(events);
> - return true;
> -}
> diff --git a/vl.c b/vl.c
> index 73e0661..fbb2771 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4034,7 +4034,7 @@ int main(int argc, char **argv, char **envp)
> }
> if (!is_daemonized()) {
> - if (!trace_backend_init(trace_events, trace_file)) {
> + if (!trace_init_backends(trace_events, trace_file)) {
> exit(1);
> }
> }
> @@ -4549,7 +4549,7 @@ int main(int argc, char **argv, char **envp)
> os_setup_post();
> if (is_daemonized()) {
> - if (!trace_backend_init(trace_events, trace_file)) {
> + if (!trace_init_backends(trace_events, trace_file)) {
> exit(1);
> }
> }
--
"And it's much the same thing with knowledge, for whenever you learn
something new, the whole world becomes that much richer."
-- The Princess of Pure Reason, as told by Norton Juster in The Phantom
Tollbooth