[PATCH v3 3/5] perf/sdt: Show SDT cache contents

From: Hemant Kumar
Date: Fri Oct 10 2014 - 06:59:18 EST


This patch adds support to dump the SDT cache onto sdtout.
The cache data is read into a hash_list and then, it iterates through
the hash_list to dump the data onto stdout.

# ./perf sdt-cache --dump

/usr/lib64/libc-2.16.so :
%libc:lll_futex_wake
%libc:longjmp_target
%libc:longjmp
%libc:lll_lock_wait_private
%libc:lll_futex_wake
%libc:longjmp_target
%libc:longjmp
%libc:setjmp

Signed-off-by: Hemant Kumar <hemant@xxxxxxxxxxxxxxxxxx>
---
tools/perf/Documentation/perf-sdt-cache.txt | 7 +++-
tools/perf/builtin-sdt-cache.c | 27 +++++++++++++++
tools/perf/util/parse-events.h | 1 +
tools/perf/util/sdt.c | 48 +++++++++++++++++++++++++++
4 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-sdt-cache.txt b/tools/perf/Documentation/perf-sdt-cache.txt
index 08b9985..e57a867 100644
--- a/tools/perf/Documentation/perf-sdt-cache.txt
+++ b/tools/perf/Documentation/perf-sdt-cache.txt
@@ -9,11 +9,13 @@ SYNOPSIS
--------
[verse]
'perf sdt-cache --add <file_name>'
+'perf sdt-cache --dump'

DESCRIPTION
-----------
This command manages the SDT events cache. It can add/remove SDT events
-associated with an ELF to the cache.
+associated with an ELF to the cache. It can also dump the SDT events' cache
+onto stdout.

OPTIONS
-------
@@ -21,6 +23,9 @@ OPTIONS
--add::
Add SDT events in the specified file to the cache. Takes file name
as an argument.
+-D::
+--dump::
+ Dump the contents of SDT events cache onto stdout.

SEE ALSO
--------
diff --git a/tools/perf/builtin-sdt-cache.c b/tools/perf/builtin-sdt-cache.c
index 0e012f6..31041db 100644
--- a/tools/perf/builtin-sdt-cache.c
+++ b/tools/perf/builtin-sdt-cache.c
@@ -16,6 +16,7 @@
/* Session management structure */
static struct {
bool add;
+ bool dump;
const char *target;
} params;

@@ -28,6 +29,15 @@ static int opt_add_sdt_events(const struct option *opt __maybe_unused,
return 0;
}

+static int opt_show_sdt_events(const struct option *opt __maybe_unused,
+ const char *str, int unset __maybe_unused)
+{
+ if (str)
+ pr_err("Unknown option %s\n", str);
+ params.dump = true;
+ return 0;
+}
+
int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused)
{
int ret;
@@ -35,10 +45,14 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused
OPT_CALLBACK('a', "add", NULL, "filename",
"add SDT events from a file.",
opt_add_sdt_events),
+ OPT_CALLBACK_NOOPT('D', "dump", NULL, "show SDT events",
+ "Read SDT events from cache and display.",
+ opt_show_sdt_events),
OPT_END()
};
const char * const sdt_cache_usage[] = {
"perf sdt-cache --add filename",
+ "perf sd-cache --dump",
NULL
};

@@ -50,9 +64,22 @@ int cmd_sdt_cache(int argc, const char **argv, const char *prefix __maybe_unused

symbol__elf_init();
if (params.add) {
+ if (params.dump) {
+ pr_err("Error: Don't use --dump with --add\n");
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+ }
+
ret = add_sdt_events(params.target);
if (ret < 0)
pr_err("Cannot add SDT events to cache\n");
+ } else if (params.dump) {
+ if (argc == 0) {
+ ret = dump_sdt_events();
+ if (ret < 0)
+ pr_err("Cannot dump SDT event cache\n");
+ } else
+ usage_with_options(sdt_cache_usage, sdt_cache_options);
+
} else
usage_with_options(sdt_cache_usage, sdt_cache_options);
return 0;
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index e6efe2c..f43e6aa 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -110,5 +110,6 @@ extern int is_valid_tracepoint(const char *event_string);
extern int valid_debugfs_mount(const char *debugfs);

int add_sdt_events(const char *file);
+int dump_sdt_events(void);

#endif /* __PERF_PARSE_EVENTS_H */
diff --git a/tools/perf/util/sdt.c b/tools/perf/util/sdt.c
index 626f07e..4e64f3e 100644
--- a/tools/perf/util/sdt.c
+++ b/tools/perf/util/sdt.c
@@ -607,3 +607,51 @@ out:
file_hash_list__cleanup(&file_hash);
return ret;
}
+
+/**
+ * file_hash_list__display: Dump the entries of file_hash list
+ * @file_hash: file hash list
+ *
+ * Iterate through each of the entries and the chains and dump
+ * onto stdscr.
+ */
+static void file_hash_list__display(struct hash_table *file_hash)
+{
+ struct file_sdt_ent *file_pos;
+ struct list_head *sdt_head;
+ struct hlist_head *ent_head;
+ struct sdt_note *sdt_ptr;
+ int i;
+
+ /* Go through all entries */
+ for (i = 0; i < SDT_HASH_SIZE; i++) {
+ /* Obtain the list head */
+ ent_head = &file_hash->ent[i];
+
+ /* ':' are used here as delimiters */
+ hlist_for_each_entry(file_pos, ent_head, file_list) {
+ fprintf(stdout, "%s:\n", file_pos->name);
+ sdt_head = &file_pos->sdt_list;
+ list_for_each_entry(sdt_ptr, sdt_head, note_list) {
+ fprintf(stdout, "\t%%%s:%s\n",
+ sdt_ptr->provider, sdt_ptr->name);
+ }
+ printf("\n");
+ }
+ }
+}
+
+/**
+ * dump_sdt_events: Dump the SDT events on stdout
+ */
+int dump_sdt_events(void)
+{
+ struct hash_table file_hash;
+ int ret;
+
+ ret = file_hash_list__init(&file_hash);
+ if (!ret)
+ file_hash_list__display(&file_hash);
+ file_hash_list__cleanup(&file_hash);
+ return ret;
+}

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