Re: [PATCH 3/2] perf_counters: add debugfs dir option

From: Frederic Weisbecker
Date: Wed Jul 08 2009 - 20:47:31 EST

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On Wed, Jul 08, 2009 at 04:17:43PM -0400, Jason Baron wrote:
> On Tue, Jul 07, 2009 at 10:29:20AM +0200, Peter Zijlstra wrote:
> > On Mon, 2009-07-06 at 17:12 -0400, Jason Baron wrote:
> > > Add support to 'perf list' and 'perf stat' for kernel tracepoints. The
> > > implementation creates a 'for_each_subsystem' and 'for_each_event' for
> > > easy iteration over the tracepoints. The debugfs filesystem must be mounted
> > > at '/sys/kernel/debug'. We can add an optional search path in the future.
> >
> > I don't have a single machine that has that mount point.
> >
> >
>
> ok, The patch below adds support for a 'PERF_DIR_DEBUGFS' environment
> variable. It also adds a command line for '--debugfs-dir' and
> '--debugfs-dir='. By default 'perf' continues to look in
> /sys/kernel/debug, which I believe is most common.
>
> thanks,
>
> -Jason
>
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>

Or why not parsing /etc/mtab ?

Thanks.

>
>
> tools/perf/perf.c | 16 ++++++++
> tools/perf/util/cache.h | 1 +
> tools/perf/util/parse-events.c | 78
> ++++++++++++++++++++++++----------------
> 3 files changed, 62 insertions(+), 33 deletions(-)
>
>
>
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index c565678..29876ee 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -122,6 +122,20 @@ static int handle_options(const char*** argv, int* argc, int* envchanged)
> setenv(PERF_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
> if (envchanged)
> *envchanged = 1;
> + } else if (!strcmp(cmd, "--debugfs-dir")) {
> + if (*argc < 2) {
> + fprintf(stderr, "No directory given for --debugfs-dir.\n");
> + usage(perf_usage_string);
> + }
> + setenv(PERF_DEBUGFS_ENVIRONMENT, (*argv)[1], 1);
> + if (envchanged)
> + *envchanged = 1;
> + (*argv)++;
> + (*argc)--;
> + } else if (!prefixcmp(cmd, "--debugfs-dir=")) {
> + setenv(PERF_DEBUGFS_ENVIRONMENT, cmd + 14, 1);
> + if (envchanged)
> + *envchanged = 1;
> } else {
> fprintf(stderr, "Unknown option: %s\n", cmd);
> usage(perf_usage_string);
> @@ -354,7 +368,7 @@ int main(int argc, const char **argv)
> cmd = perf_extract_argv0_path(argv[0]);
> if (!cmd)
> cmd = "perf-help";
> -
> + setenv(PERF_DEBUGFS_ENVIRONMENT, "/sys/kernel/debug/", 0);
> /*
> * "perf-xxxx" is the same as "perf xxxx", but we obviously:
> *
> diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
> index 161d5f4..4ba4b3e 100644
> --- a/tools/perf/util/cache.h
> +++ b/tools/perf/util/cache.h
> @@ -18,6 +18,7 @@
> #define PERFATTRIBUTES_FILE ".perfattributes"
> #define INFOATTRIBUTES_FILE "info/attributes"
> #define ATTRIBUTE_MACRO_PREFIX "[attr]"
> +#define PERF_DEBUGFS_ENVIRONMENT "PERF_DIR_DEBUGFS"
>
> typedef int (*config_fn_t)(const char *, const char *, void *);
> extern int perf_default_config(const char *, const char *, void *);
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index d454eac..54b6c23 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -5,6 +5,7 @@
> #include "parse-events.h"
> #include "exec_cmd.h"
> #include "string.h"
> +#include "cache.h"
>
> extern char *strcasestr(const char *haystack, const char *needle);
>
> @@ -12,8 +13,6 @@ int nr_counters;
>
> struct perf_counter_attr attrs[MAX_COUNTERS];
>
> -static char default_debugfs_path[] = "/sys/kernel/debug/tracing/events";
> -
> struct event_symbol {
> u8 type;
> u64 config;
> @@ -21,6 +20,8 @@ struct event_symbol {
> char *alias;
> };
>
> +static char debugfs_path[MAXPATHLEN];
> +
> #define CHW(x) .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_##x
> #define CSW(x) .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_##x
>
> @@ -112,30 +113,38 @@ static unsigned long hw_cache_stat[C(MAX)] = {
> [C(BPU)] = (CACHE_READ),
> };
>
> -#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st) \
> - while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next) \
> - if (sprintf(file, "%s/%s", default_debugfs_path, sys_dirent.d_name) && \
> - (stat(file, &st) == 0) && (S_ISDIR(st.st_mode)) && \
> - (strcmp(sys_dirent.d_name, ".") != 0) && \
> +#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st) \
> + while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next) \
> + if (snprintf(file, MAXPATHLEN, "%s/%s/%s", \
> + getenv(PERF_DEBUGFS_ENVIRONMENT), "tracing/events", \
> + sys_dirent.d_name) && \
> + (stat(file, &st) == 0) && (S_ISDIR(st.st_mode)) && \
> + (strcmp(sys_dirent.d_name, ".") != 0) && \
> (strcmp(sys_dirent.d_name, "..") != 0))
>
> -#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next, file, st) \
> - while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next) \
> - if (sprintf(file, "%s/%s/%s", default_debugfs_path, sys_dirent.d_name, \
> - evt_dirent.d_name) && \
> - (stat(file, &st) == 0) && (S_ISDIR(st.st_mode)) && \
> - (strcmp(evt_dirent.d_name, ".") != 0) && \
> +#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next, file, st) \
> + while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next) \
> + if (snprintf(file, MAXPATHLEN, "%s/%s/%s/%s", \
> + getenv(PERF_DEBUGFS_ENVIRONMENT), "tracing/events", \
> + sys_dirent.d_name, evt_dirent.d_name) && \
> + (stat(file, &st) == 0) && (S_ISDIR(st.st_mode)) && \
> + (strcmp(evt_dirent.d_name, ".") != 0) && \
> (strcmp(evt_dirent.d_name, "..") != 0))
>
> -#define MAX_PATH_LENGTH (strlen(default_debugfs_path) + 3 + \
> - (3 * (strlen(sys_dirent.d_name))) + 1)
> #define MAX_EVENT_LENGTH 30
>
> -static int valid_debugfs_mount(void)
> +static void set_debugfs_path(void)
> +{
> + snprintf(debugfs_path, MAXPATHLEN, "%s/%s",
> + getenv(PERF_DEBUGFS_ENVIRONMENT),
> + "tracing/events");
> +}
> +
> +static int valid_debugfs_mount(const char *mount)
> {
> struct statfs st_fs;
>
> - if (statfs(default_debugfs_path, &st_fs) < 0)
> + if (statfs(mount, &st_fs) < 0)
> return -ENOENT;
> else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
> return -ENOENT;
> @@ -151,12 +160,13 @@ static char *tracepoint_id_to_name(u64 config)
> char id_buf[4];
> int fd;
> long long id;
> - char evt_path[MAX_PATH_LENGTH];
> + char evt_path[MAXPATHLEN];
>
> - if (valid_debugfs_mount())
> + set_debugfs_path();
> + if (valid_debugfs_mount(debugfs_path))
> return "unkown";
>
> - sys_dir = opendir(default_debugfs_path);
> + sys_dir = opendir(debugfs_path);
> if (!sys_dir)
> goto cleanup;
> for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
> @@ -165,8 +175,9 @@ static char *tracepoint_id_to_name(u64 config)
> goto cleanup;
> for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,
> evt_path, st) {
> - sprintf(evt_path, "%s/%s/%s/id", default_debugfs_path,
> - sys_dirent.d_name, evt_dirent.d_name);
> + snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id",
> + debugfs_path, sys_dirent.d_name,
> + evt_dirent.d_name);
> fd = open(evt_path, O_RDONLY);
> if (fd < 0)
> continue;
> @@ -362,9 +373,10 @@ static int parse_tracepoint_event(const char **strp,
> int fd;
> unsigned int sys_length, evt_length;
> u64 id;
> - char evt_path[MAX_PATH_LENGTH];
> + char evt_path[MAXPATHLEN];
>
> - if (valid_debugfs_mount())
> + set_debugfs_path();
> + if (valid_debugfs_mount(debugfs_path))
> return 0;
>
> evt_name = strchr(*strp, ':');
> @@ -381,7 +393,7 @@ static int parse_tracepoint_event(const char **strp,
> } else
> return 0;
>
> - sys_dir = opendir(default_debugfs_path);
> + sys_dir = opendir(debugfs_path);
> if (!sys_dir)
> goto cleanup;
> for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
> @@ -392,10 +404,11 @@ static int parse_tracepoint_event(const char **strp,
> for_each_event(sys_dirent, evt_dir, evt_dirent,
> evt_next, evt_path, st) {
> if (strcmp(evt_dirent.d_name, evt_name) == 0) {
> - sprintf(evt_path, "%s/%s/%s/id",
> - default_debugfs_path,
> - sys_dirent.d_name,
> - evt_dirent.d_name);
> + snprintf(evt_path, MAXPATHLEN,
> + "%s/%s/%s/id",
> + debugfs_path,
> + sys_dirent.d_name,
> + evt_dirent.d_name);
> fd = open(evt_path, O_RDONLY);
> if (fd < 0)
> continue;
> @@ -589,12 +602,13 @@ static void print_tracepoint_events(void)
> DIR *sys_dir, *evt_dir;
> struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
> struct stat st;
> - char evt_path[MAX_PATH_LENGTH];
> + char evt_path[MAXPATHLEN];
>
> - if (valid_debugfs_mount())
> + set_debugfs_path();
> + if (valid_debugfs_mount(debugfs_path))
> return;
>
> - sys_dir = opendir(default_debugfs_path);
> + sys_dir = opendir(debugfs_path);
> if (!sys_dir)
> goto cleanup;
> for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
>
>

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Next message: Tejun Heo: "Re: [PATCH 3/4] block: implement mixed merge of different failfastrequests"
Previous message: Tejun Heo: "Re: [PATCH 2/4] block: use the same failfast bits for bio and request"
In reply to: Jason Baron: "[PATCH 3/2] perf_counters: add debugfs dir option"
Next in thread: Jason Baron: "Re: [PATCH 3/2] perf_counters: add debugfs dir option"
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