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authorPaul Clarke <pc@us.ibm.com>2017-04-25 13:15:49 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-05-02 18:23:11 -0300
commitd80406453ad4a69932dc17a617d5b7bc7ae80b8f (patch)
tree43551c93dab399be05e0979ef1e610a3bfc3228a
parentb843f62ad942f3879c2d7acd27b44f931c609685 (diff)
perf symbols: Allow user probes on versioned symbols
Symbol versioning, as in glibc, results in symbols being defined as: <real symbol>@[@]<version> (Note that "@@" identifies a default symbol, if the symbol name is repeated.) perf is currently unable to deal with this, and is unable to create user probes at such symbols: -- $ nm /lib/powerpc64le-linux-gnu/libpthread.so.0 | grep pthread_create 0000000000008d30 t __pthread_create_2_1 0000000000008d30 T pthread_create@@GLIBC_2.17 $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create probe-definition(0): pthread_create symbol:pthread_create file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Open Debuginfo file: /usr/lib/debug/lib/powerpc64le-linux-gnu/libpthread-2.19.so Try to find probe point from debuginfo. Probe point 'pthread_create' not found. Error: Failed to add events. Reason: No such file or directory (Code: -2) -- One is not able to specify the fully versioned symbol, either, due to syntactic conflicts with other uses of "@" by perf: -- $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create@@GLIBC_2.17 probe-definition(0): pthread_create@@GLIBC_2.17 Semantic error :SRC@SRC is not allowed. 0 arguments Error: Command Parse Error. Reason: Invalid argument (Code: -22) -- This patch ignores versioning for default symbols, thus allowing probes to be created for these symbols: -- $ /usr/bin/sudo ./perf probe -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create Added new event: probe_libpthread:pthread_create (on pthread_create in /lib/powerpc64le-linux-gnu/libpthread-2.19.so) You can now use it in all perf tools, such as: perf record -e probe_libpthread:pthread_create -aR sleep 1 $ /usr/bin/sudo ./perf record -e probe_libpthread:pthread_create -aR ./test 2 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.052 MB perf.data (2 samples) ] $ /usr/bin/sudo ./perf script test 2915 [000] 19124.260729: probe_libpthread:pthread_create: (3fff99248d38) test 2916 [000] 19124.260962: probe_libpthread:pthread_create: (3fff99248d38) $ /usr/bin/sudo ./perf probe --del=probe_libpthread:pthread_create Removed event: probe_libpthread:pthread_create -- Committer note: Change the variable storing the result of strlen() to 'int', to fix the build on debian:experimental-x-mipsel, fedora:24-x-ARC-uClibc, ubuntu:16.04-x-arm, etc: util/symbol.c: In function 'symbol__match_symbol_name': util/symbol.c:422:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (len < versioning - name) ^ Signed-off-by: Paul A. Clarke <pc@us.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: David Ahern <dsahern@gmail.com> Link: http://lkml.kernel.org/r/c2b18d9c-17f8-9285-4868-f58b6359ccac@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/arch/powerpc/util/sym-handling.c12
-rw-r--r--tools/perf/util/map.c5
-rw-r--r--tools/perf/util/map.h5
-rw-r--r--tools/perf/util/symbol.c61
-rw-r--r--tools/perf/util/symbol.h11
5 files changed, 74 insertions, 20 deletions
diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 39dbe512b9fc..bf9a2594572c 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -52,6 +52,18 @@ int arch__compare_symbol_names(const char *namea, const char *nameb)
return strcmp(namea, nameb);
}
+
+int arch__compare_symbol_names_n(const char *namea, const char *nameb,
+ unsigned int n)
+{
+ /* Skip over initial dot */
+ if (*namea == '.')
+ namea++;
+ if (*nameb == '.')
+ nameb++;
+
+ return strncmp(namea, nameb, n);
+}
#endif
#if defined(_CALL_ELF) && _CALL_ELF == 2
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index ebfa5d92358a..2179b2deb730 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -325,11 +325,6 @@ int map__load(struct map *map)
return 0;
}
-int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
-{
- return strcmp(namea, nameb);
-}
-
struct symbol *map__find_symbol(struct map *map, u64 addr)
{
if (map__load(map) < 0)
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index c8a5a644c0a9..f9e8ac8a52cd 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -130,13 +130,14 @@ struct thread;
*/
#define __map__for_each_symbol_by_name(map, sym_name, pos) \
for (pos = map__find_symbol_by_name(map, sym_name); \
- pos && arch__compare_symbol_names(pos->name, sym_name) == 0; \
+ pos && \
+ !symbol__match_symbol_name(pos->name, sym_name, \
+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY); \
pos = symbol__next_by_name(pos))
#define map__for_each_symbol_by_name(map, sym_name, pos) \
__map__for_each_symbol_by_name(map, sym_name, (pos))
-int arch__compare_symbol_names(const char *namea, const char *nameb);
void map__init(struct map *map, enum map_type type,
u64 start, u64 end, u64 pgoff, struct dso *dso);
struct map *map__new(struct machine *machine, u64 start, u64 len,
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index b349e8eda0e2..8f2b068ff756 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -90,6 +90,17 @@ static int prefix_underscores_count(const char *str)
return tail - str;
}
+int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
+{
+ return strcmp(namea, nameb);
+}
+
+int __weak arch__compare_symbol_names_n(const char *namea, const char *nameb,
+ unsigned int n)
+{
+ return strncmp(namea, nameb, n);
+}
+
int __weak arch__choose_best_symbol(struct symbol *syma,
struct symbol *symb __maybe_unused)
{
@@ -399,8 +410,26 @@ static void symbols__sort_by_name(struct rb_root *symbols,
}
}
+int symbol__match_symbol_name(const char *name, const char *str,
+ enum symbol_tag_include includes)
+{
+ const char *versioning;
+
+ if (includes == SYMBOL_TAG_INCLUDE__DEFAULT_ONLY &&
+ (versioning = strstr(name, "@@"))) {
+ int len = strlen(str);
+
+ if (len < versioning - name)
+ len = versioning - name;
+
+ return arch__compare_symbol_names_n(name, str, len);
+ } else
+ return arch__compare_symbol_names(name, str);
+}
+
static struct symbol *symbols__find_by_name(struct rb_root *symbols,
- const char *name)
+ const char *name,
+ enum symbol_tag_include includes)
{
struct rb_node *n;
struct symbol_name_rb_node *s = NULL;
@@ -414,11 +443,11 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
int cmp;
s = rb_entry(n, struct symbol_name_rb_node, rb_node);
- cmp = arch__compare_symbol_names(name, s->sym.name);
+ cmp = symbol__match_symbol_name(s->sym.name, name, includes);
- if (cmp < 0)
+ if (cmp > 0)
n = n->rb_left;
- else if (cmp > 0)
+ else if (cmp < 0)
n = n->rb_right;
else
break;
@@ -427,16 +456,17 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
if (n == NULL)
return NULL;
- /* return first symbol that has same name (if any) */
- for (n = rb_prev(n); n; n = rb_prev(n)) {
- struct symbol_name_rb_node *tmp;
+ if (includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY)
+ /* return first symbol that has same name (if any) */
+ for (n = rb_prev(n); n; n = rb_prev(n)) {
+ struct symbol_name_rb_node *tmp;
- tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
- if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
- break;
+ tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
+ if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
+ break;
- s = tmp;
- }
+ s = tmp;
+ }
return &s->sym;
}
@@ -503,7 +533,12 @@ struct symbol *symbol__next_by_name(struct symbol *sym)
struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
const char *name)
{
- return symbols__find_by_name(&dso->symbol_names[type], name);
+ struct symbol *s = symbols__find_by_name(&dso->symbol_names[type], name,
+ SYMBOL_TAG_INCLUDE__NONE);
+ if (!s)
+ s = symbols__find_by_name(&dso->symbol_names[type], name,
+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY);
+ return s;
}
void dso__sort_by_name(struct dso *dso, enum map_type type)
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 7acd70fce68e..41ebba9a2eb2 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -348,8 +348,19 @@ void arch__sym_update(struct symbol *s, GElf_Sym *sym);
#define SYMBOL_A 0
#define SYMBOL_B 1
+int arch__compare_symbol_names(const char *namea, const char *nameb);
+int arch__compare_symbol_names_n(const char *namea, const char *nameb,
+ unsigned int n);
int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb);
+enum symbol_tag_include {
+ SYMBOL_TAG_INCLUDE__NONE = 0,
+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY
+};
+
+int symbol__match_symbol_name(const char *namea, const char *nameb,
+ enum symbol_tag_include includes);
+
/* structure containing an SDT note's info */
struct sdt_note {
char *name; /* name of the note*/