Commit 638e2b99 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf script: Add option to list dlfilters 



Add option --list-dlfilters to list dlfilters in the current directory or
the exec-path e.g. ~/libexec/perf-core/dlfilters. Use with option -v (must
come before option --list-dlfilters) to show long descriptions.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-4-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9bde93a7

tools/perf/Documentation/perf-dlfilter.txt

+4 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ int start(void **data, void *ctx); 
int stop(void *data, void *ctx);

int filter_event(void *data, const struct perf_dlfilter_sample *sample, void *ctx);

int filter_event_early(void *data, const struct perf_dlfilter_sample *sample, void *ctx);

const char *filter_description(const char **long_description);

----



If implemented, 'start' will be called at the beginning, before any
@@ -59,6 +60,9 @@ error code. 'data' is set by 'start'. 'ctx' is needed for calls to 
'filter_event_early' is the same as 'filter_event' except it is called before

internal filtering.



If implemented, 'filter_description' should return a one-line description

of the filter, and optionally a longer description.



The perf_dlfilter_sample structure

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

tools/perf/Documentation/perf-script.txt

+4 −0
Original line number Diff line number Diff line
@@ -102,6 +102,10 @@ OPTIONS 
	Filter sample events using the given shared object file.

	Refer linkperf:perf-dlfilter[1]



--list-dlfilters=::

        Display a list of available dlfilters. Use with option -v (must come

        before option --list-dlfilters) to show long descriptions.



-a::

        Force system-wide collection.  Scripts run without a <command>

        normally use -a by default, while scripts run with a <command>

tools/perf/builtin-script.c

+2 −0
Original line number Diff line number Diff line
@@ -3631,6 +3631,8 @@ int cmd_script(int argc, const char **argv) 
		    "show latency attributes (irqs/preemption disabled, etc)"),

	OPT_CALLBACK_NOOPT('l', "list", NULL, NULL, "list available scripts",

			   list_available_scripts),

	OPT_CALLBACK_NOOPT(0, "list-dlfilters", NULL, NULL, "list available dlfilters",

			   list_available_dlfilters),

	OPT_CALLBACK('s', "script", NULL, "name",

		     "script file name (lang:script name, script name, or *)",

		     parse_scriptname),

tools/perf/util/dlfilter.c

+116 −1
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ 
#include <dlfcn.h>

#include <stdlib.h>

#include <string.h>

#include <dirent.h>

#include <subcmd/exec-cmd.h>

#include <linux/zalloc.h>

#include <linux/build_bug.h>
@@ -136,6 +138,35 @@ static const struct perf_dlfilter_fns perf_dlfilter_fns = { 
	.resolve_addr    = dlfilter__resolve_addr,

};



static char *find_dlfilter(const char *file)

{

	char path[PATH_MAX];

	char *exec_path;



	if (strchr(file, '/'))

		goto out;



	if (!access(file, R_OK)) {

		/*

		 * Prepend "./" so that dlopen will find the file in the

		 * current directory.

		 */

		snprintf(path, sizeof(path), "./%s", file);

		file = path;

		goto out;

	}



	exec_path = get_argv_exec_path();

	if (!exec_path)

		goto out;

	snprintf(path, sizeof(path), "%s/dlfilters/%s", exec_path, file);

	free(exec_path);

	if (!access(path, R_OK))

		file = path;

out:

	return strdup(file);

}



#define CHECK_FLAG(x) BUILD_BUG_ON((u64)PERF_DLFILTER_FLAG_ ## x != (u64)PERF_IP_FLAG_ ## x)



static int dlfilter__init(struct dlfilter *d, const char *file)
@@ -155,7 +186,7 @@ static int dlfilter__init(struct dlfilter *d, const char *file) 
	CHECK_FLAG(VMEXIT);



	memset(d, 0, sizeof(*d));

	d->file = strdup(file);

	d->file = find_dlfilter(file);

	if (!d->file)

		return -1;

	return 0;
@@ -333,3 +364,87 @@ int dlfilter__do_filter_event(struct dlfilter *d, 


	return ret;

}



static bool get_filter_desc(const char *dirname, const char *name,

			    char **desc, char **long_desc)

{

	char path[PATH_MAX];

	void *handle;

	const char *(*desc_fn)(const char **long_description);



	snprintf(path, sizeof(path), "%s/%s", dirname, name);

	handle = dlopen(path, RTLD_NOW);

	if (!handle || !(dlsym(handle, "filter_event") || dlsym(handle, "filter_event_early")))

		return false;

	desc_fn = dlsym(handle, "filter_description");

	if (desc_fn) {

		const char *dsc;

		const char *long_dsc;



		dsc = desc_fn(&long_dsc);

		if (dsc)

			*desc = strdup(dsc);

		if (long_dsc)

			*long_desc = strdup(long_dsc);

	}

	dlclose(handle);

	return true;

}



static void list_filters(const char *dirname)

{

	struct dirent *entry;

	DIR *dir;



	dir = opendir(dirname);

	if (!dir)

		return;



	while ((entry = readdir(dir)) != NULL)

	{

		size_t n = strlen(entry->d_name);

		char *long_desc = NULL;

		char *desc = NULL;



		if (entry->d_type == DT_DIR || n < 4 ||

		    strcmp(".so", entry->d_name + n - 3))

			continue;

		if (!get_filter_desc(dirname, entry->d_name, &desc, &long_desc))

			continue;

		printf("  %-36s %s\n", entry->d_name, desc ? desc : "");

		if (verbose) {

			char *p = long_desc;

			char *line;



			while ((line = strsep(&p, "\n")) != NULL)

				printf("%39s%s\n", "", line);

		}

		free(long_desc);

		free(desc);

	}



	closedir(dir);

}



int list_available_dlfilters(const struct option *opt __maybe_unused,

			     const char *s __maybe_unused,

			     int unset __maybe_unused)

{

	char path[PATH_MAX];

	char *exec_path;



	printf("List of available dlfilters:\n");



	list_filters(".");



	exec_path = get_argv_exec_path();

	if (!exec_path)

		goto out;

	snprintf(path, sizeof(path), "%s/dlfilters", exec_path);



	list_filters(path);



	free(exec_path);

out:

	exit(0);

}

tools/perf/util/dlfilter.h

+2 −0
Original line number Diff line number Diff line
@@ -88,4 +88,6 @@ static inline int dlfilter__filter_event_early(struct dlfilter *d, 
	return dlfilter__do_filter_event(d, event, sample, evsel, machine, al, addr_al, true);

}



int list_available_dlfilters(const struct option *opt, const char *s, int unset);



#endif