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Commit 23e8ec0d authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
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perf probe: Add perf probe command support without libdwarf 



Enables 'perf probe' even if libdwarf is not installed. If libdwarf is
not found, 'perf probe' just disables dwarf support. Users can use
'perf probe' to set up new events by using kprobe_events format.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
LKML-Reference: <20091007222830.1684.25665.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 4ea42b18

tools/perf/Makefile

+3 −3
Original line number Diff line number Diff line
@@ -385,6 +385,7 @@ BUILTIN_OBJS += builtin-stat.o 
BUILTIN_OBJS += builtin-timechart.o

BUILTIN_OBJS += builtin-top.o

BUILTIN_OBJS += builtin-trace.o

BUILTIN_OBJS += builtin-probe.o



PERFLIBS = $(LIB_FILE)
@@ -420,13 +421,12 @@ ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * 
endif



ifneq ($(shell sh -c "(echo '\#include <libdwarf/dwarf.h>'; echo '\#include <libdwarf/libdwarf.h>'; echo 'int main(void) { Dwarf_Debug dbg; Dwarf_Error err; dwarf_init(0, DW_DLC_READ, 0, 0, &dbg, &err); return (long)dbg; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -ldwarf -lelf -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y)

	msg := $(warning No libdwarf.h found, disables probe subcommand. Please install libdwarf-dev/libdwarf-devel);

	msg := $(warning No libdwarf.h found, disables dwarf support. Please install libdwarf-dev/libdwarf-devel);

	BASIC_CFLAGS += -DNO_LIBDWARF

else

	EXTLIBS += -lelf -ldwarf

	LIB_H += util/probe-finder.h

	LIB_OBJS += util/probe-finder.o

	BUILTIN_OBJS += builtin-probe.o

	BASIC_CFLAGS += -DSUPPORT_DWARF

endif



ifdef NO_DEMANGLE

tools/perf/builtin-probe.c

+35 −7
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ const char *default_search_path[NR_SEARCH_PATH] = { 
static struct {

	char *vmlinux;

	char *release;

	int need_dwarf;

	int nr_probe;

	struct probe_point probes[MAX_PROBES];

	char *events[MAX_PROBES];
@@ -162,6 +163,8 @@ static int parse_probepoint(const struct option *opt __used, 
		      pp->function, pp->file, pp->offset);

	}

	free(argv[1]);

	if (pp->file)

		session.need_dwarf = 1;



	/* Copy arguments */

	pp->nr_args = argc - 2;
@@ -173,15 +176,19 @@ static int parse_probepoint(const struct option *opt __used, 
	}



	/* Ensure return probe has no C argument */

	if (retp)

	for (i = 0; i < pp->nr_args; i++)

			if (is_c_varname(pp->args[i]))

		if (is_c_varname(pp->args[i])) {

			if (retp)

				semantic_error("You can't specify local"

						" variable for kretprobe");

			session.need_dwarf = 1;

		}



	debug("%d arguments\n", pp->nr_args);

	return 0;

}



#ifndef NO_LIBDWARF

static int open_default_vmlinux(void)

{

	struct utsname uts;
@@ -209,6 +216,7 @@ static int open_default_vmlinux(void) 
	}

	return fd;

}

#endif



static const char * const probe_usage[] = {

	"perf probe [<options>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]",
@@ -216,10 +224,16 @@ static const char * const probe_usage[] = { 
};



static const struct option options[] = {

#ifndef NO_LIBDWARF

	OPT_STRING('k', "vmlinux", &session.vmlinux, "file",

		"vmlinux/module pathname"),

#endif

	OPT_CALLBACK('P', "probe", NULL,

#ifdef NO_LIBDWARF

		"p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",

#else

		"p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",

#endif

		"probe point definition, where\n"

		"\t\tp:\tkprobe probe\n"

		"\t\tr:\tkretprobe probe\n"
@@ -227,9 +241,13 @@ static const struct option options[] = { 
		"\t\tNAME:\tEvent name\n"

		"\t\tFUNC:\tFunction name\n"

		"\t\tOFFS:\tOffset from function entry (in byte)\n"

#ifdef NO_LIBDWARF

		"\t\tARG:\tProbe argument (only \n"

#else

		"\t\tSRC:\tSource code path\n"

		"\t\tLINE:\tLine number\n"

		"\t\tARG:\tProbe argument (local variable name or\n"

#endif

		"\t\t\tkprobe-tracer argument format is supported.)\n",

		parse_probepoint),

	OPT_END()
@@ -279,7 +297,7 @@ static int synthesize_probepoint(struct probe_point *pp) 


int cmd_probe(int argc, const char **argv, const char *prefix __used)

{

	int i, j, fd, ret, need_dwarf = 0;

	int i, j, fd, ret;

	struct probe_point *pp;

	char buf[MAX_CMDLEN];
@@ -288,12 +306,19 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
	if (argc || session.nr_probe == 0)

		usage_with_options(probe_usage, options);



	/* Synthesize return probes */

#ifdef NO_LIBDWARF

	if (session.need_dwarf)

		semantic_error("Dwarf-analysis is not supported");

#endif



	/* Synthesize probes without dwarf */

	for (j = 0; j < session.nr_probe; j++) {

#ifndef NO_LIBDWARF

		if (session.events[j][0] != 'r') {

			need_dwarf = 1;

			session.need_dwarf = 1;

			continue;

		}

#endif

		ret = synthesize_probepoint(&session.probes[j]);

		if (ret == -E2BIG)

			semantic_error("probe point is too long.");
@@ -303,7 +328,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
		}

	}



	if (!need_dwarf)

#ifndef NO_LIBDWARF

	if (!session.need_dwarf)

		goto setup_probes;



	if (session.vmlinux)
@@ -332,6 +358,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
	close(fd);



setup_probes:

#endif /* !NO_LIBDWARF */



	/* Settng up probe points */

	snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);

	fd = open(buf, O_WRONLY, O_APPEND);

tools/perf/perf.c

+0 −2
Original line number Diff line number Diff line
@@ -295,9 +295,7 @@ static void handle_internal_command(int argc, const char **argv) 
		{ "version", cmd_version, 0 },

		{ "trace", cmd_trace, 0 },

		{ "sched", cmd_sched, 0 },

#ifdef SUPPORT_DWARF

		{ "probe", cmd_probe, 0 },

#endif

	};

	unsigned int i;

	static const char ext[] = STRIP_EXTENSION;

tools/perf/util/probe-finder.h

+2 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ struct probe_point { 
	char	*probes[MAX_PROBES];	/* Output buffers (will be allocated)*/

};



#ifndef NO_LIBDWARF

extern int find_probepoint(int fd, struct probe_point *pp);



#include <libdwarf/dwarf.h>
@@ -64,5 +65,6 @@ struct probe_finder { 
	char		*buf;		/* Current output buffer */

	int		len;		/* Length of output buffer */

};

#endif /* NO_LIBDWARF */



#endif /*_PROBE_FINDER_H */