[PATCH perf/core v5 04/15] perf probe: Add --cache option to cache the probe definitions

Masami Hiramatsu
2016-04-27T18:37:57Z

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Add --cache option to cache the probe definitions. This
just saves the result of the dwarf analysis to probe cache.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v5:
- Move probe_cache* definitions. (code cleanup)

Changes in v4:
- Remove cache saving failure message.
---
tools/perf/Documentation/perf-probe.txt | 4
tools/perf/builtin-probe.c | 1
tools/perf/util/build-id.c | 13 +
tools/perf/util/build-id.h | 2
tools/perf/util/probe-event.c | 126 +++++++++++--
tools/perf/util/probe-event.h | 5 +
tools/perf/util/probe-file.c | 299 +++++++++++++++++++++++++++++++
tools/perf/util/probe-file.h | 19 ++
8 files changed, 441 insertions(+), 28 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 3a8a9ba..947db6f 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -109,6 +109,10 @@ OPTIONS
Dry run. With this option, --add and --del doesn't execute actual
adding and removal operations.

+--cache::
+ Cache the probes (with --add option). Any events which successfully added
+ are also stored in the cache file.
+
--max-probes=NUM::
Set the maximum number of probe points for an event. Default is 128.

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 9af859b..6d7ab431 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -512,6 +512,7 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
"Enable symbol demangling"),
OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
"Enable kernel symbol demangling"),
+ OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
OPT_END()
};
int ret;
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 848e05f..588ff01 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -371,9 +371,8 @@ void disable_buildid_cache(void)
no_buildid_cache = true;
}

-static char *build_id_cache__dirname_from_path(const char *name,
- bool is_kallsyms, bool is_vdso,
- const char *sbuild_id)
+char *build_id_cache__dirname_from_path(const char *sbuild_id, const char *name,
+ bool is_kallsyms, bool is_vdso)
{
char *realname = (char *)name, *filename;
bool slash = is_kallsyms || is_vdso;
@@ -402,8 +401,8 @@ int build_id_cache__list_build_ids(const char *pathname,
char *dir_name;
int ret = 0;

- dir_name = build_id_cache__dirname_from_path(pathname, false, false,
- NULL);
+ dir_name = build_id_cache__dirname_from_path(NULL, pathname,
+ false, false);
if (!dir_name)
return -ENOMEM;

@@ -430,8 +429,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
goto out_free;
}

- dir_name = build_id_cache__dirname_from_path(name, is_kallsyms,
- is_vdso, sbuild_id);
+ dir_name = build_id_cache__dirname_from_path(sbuild_id, name,
+ is_kallsyms, is_vdso);
if (!dir_name)
goto out_free;

diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 64af3e2..1841524 100644
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -28,6 +28,8 @@ bool perf_session__read_build_ids(struct perf_session *session, bool with_hits);
int perf_session__write_buildid_table(struct perf_session *session, int fd);
int perf_session__cache_build_ids(struct perf_session *session);

+char *build_id_cache__dirname_from_path(const char *sbuild_id, const char *name,
+ bool is_kallsyms, bool is_vdso);
int build_id_cache__list_build_ids(const char *pathname,
struct strlist **result);
bool build_id_cache__cached(const char *sbuild_id);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 85d82f4..dc0265e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -67,7 +67,6 @@ int e_snprintf(char *str, size_t size, const char *format, ...)
return ret;
}

-static char *synthesize_perf_probe_point(struct perf_probe_point *pp);
static struct machine *host_machine;

/* Initialize symbol maps and path of vmlinux/modules */
@@ -1703,7 +1702,7 @@ char *synthesize_perf_probe_arg(struct perf_probe_arg *pa)
}

/* Compose only probe point (not argument) */
-static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
+char *synthesize_perf_probe_point(struct perf_probe_point *pp)
{
struct strbuf buf;
char *tmp;
@@ -1734,30 +1733,36 @@ static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
return strbuf_detach(&buf, NULL);
}

-#if 0
char *synthesize_perf_probe_command(struct perf_probe_event *pev)
{
- char *buf;
- int i, len, ret;
+ struct strbuf buf;
+ char *tmp;
+ int i;

- buf = synthesize_perf_probe_point(&pev->point);
- if (!buf)
- return NULL;
+ strbuf_init(&buf, 64);
+ if (pev->event)
+ strbuf_addf(&buf, "%s:%s=", pev->group ?: PERFPROBE_GROUP,
+ pev->event);
+
+ tmp = synthesize_perf_probe_point(&pev->point);
+ if (!tmp)
+ goto out;
+ strbuf_addstr(&buf, tmp);
+ free(tmp);

- len = strlen(buf);
for (i = 0; i < pev->nargs; i++) {
- ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
- pev->args[i].name);
- if (ret <= 0) {
- free(buf);
- return NULL;
- }
- len += ret;
+ tmp = synthesize_perf_probe_arg(pev->args + i);
+ if (!tmp)
+ goto out;
+ strbuf_addf(&buf, " %s", tmp);
+ free(tmp);
}

- return buf;
+ tmp = strbuf_detach(&buf, NULL);
+out:
+ strbuf_release(&buf);
+ return tmp;
}
-#endif

static int __synthesize_probe_trace_arg_ref(struct probe_trace_arg_ref *ref,
struct strbuf *buf, int depth)
@@ -2000,6 +2005,79 @@ void clear_perf_probe_event(struct perf_probe_event *pev)
memset(pev, 0, sizeof(*pev));
}

+#define strdup_or_goto(str, label) \
+({ char *__p = NULL; if (str && !(__p = strdup(str))) goto label; __p; })
+
+static int perf_probe_point__copy(struct perf_probe_point *dst,
+ struct perf_probe_point *src)
+{
+ dst->file = strdup_or_goto(src->file, out_err);
+ dst->function = strdup_or_goto(src->function, out_err);
+ dst->lazy_line = strdup_or_goto(src->lazy_line, out_err);
+ dst->line = src->line;
+ dst->retprobe = src->retprobe;
+ dst->offset = src->offset;
+ return 0;
+
+out_err:
+ clear_perf_probe_point(dst);
+ return -ENOMEM;
+}
+
+static int perf_probe_arg__copy(struct perf_probe_arg *dst,
+ struct perf_probe_arg *src)
+{
+ struct perf_probe_arg_field *field, **ppfield;
+
+ dst->name = strdup_or_goto(src->name, out_err);
+ dst->var = strdup_or_goto(src->var, out_err);
+ dst->type = strdup_or_goto(src->type, out_err);
+
+ field = src->field;
+ ppfield = &(dst->field);
+ while (field) {
+ *ppfield = zalloc(sizeof(*field));
+ if (!*ppfield)
+ goto out_err;
+ (*ppfield)->name = strdup_or_goto(field->name, out_err);
+ (*ppfield)->index = field->index;
+ (*ppfield)->ref = field->ref;
+ field = field->next;
+ ppfield = &((*ppfield)->next);
+ }
+ return 0;
+out_err:
+ return -ENOMEM;
+}
+
+int perf_probe_event__copy(struct perf_probe_event *dst,
+ struct perf_probe_event *src)
+{
+ int i;
+
+ dst->event = strdup_or_goto(src->event, out_err);
+ dst->group = strdup_or_goto(src->group, out_err);
+ dst->target = strdup_or_goto(src->target, out_err);
+ dst->uprobes = src->uprobes;
+
+ if (perf_probe_point__copy(&dst->point, &src->point) < 0)
+ goto out_err;
+
+ dst->args = zalloc(sizeof(struct perf_probe_arg) * src->nargs);
+ if (!dst->args)
+ goto out_err;
+ dst->nargs = src->nargs;
+
+ for (i = 0; i < src->nargs; i++)
+ if (perf_probe_arg__copy(&dst->args[i], &src->args[i]) < 0)
+ goto out_err;
+ return 0;
+
+out_err:
+ clear_perf_probe_event(dst);
+ return -ENOMEM;
+}
+
void clear_probe_trace_event(struct probe_trace_event *tev)
{
struct probe_trace_arg_ref *ref, *next;
@@ -2403,6 +2481,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
{
int i, fd, ret;
struct probe_trace_event *tev = NULL;
+ struct probe_cache *cache = NULL;
struct strlist *namelist;

fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
@@ -2444,6 +2523,14 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
}
if (ret == -EINVAL && pev->uprobes)
warn_uprobe_event_compat(tev);
+ if (ret == 0 && probe_conf.cache) {
+ cache = probe_cache__new(pev->target);
+ if (cache) {
+ probe_cache__add_entry(cache, pev, tevs, ntevs);
+ probe_cache__commit(cache);
+ probe_cache__delete(cache);
+ }
+ }

strlist__delete(namelist);
close_out:
@@ -2472,9 +2559,6 @@ static int find_probe_functions(struct map *map, char *name,
return found;
}

-#define strdup_or_goto(str, label) \
- ({ char *__p = strdup(str); if (!__p) goto label; __p; })
-
void __weak arch__fix_tev_from_maps(struct perf_probe_event *pev __maybe_unused,
struct probe_trace_event *tev __maybe_unused,
struct map *map __maybe_unused) { }
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index e220962..c451223 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -12,6 +12,7 @@ struct probe_conf {
bool show_location_range;
bool force_add;
bool no_inlines;
+ bool cache;
int max_probes;
};
extern struct probe_conf probe_conf;
@@ -121,6 +122,10 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev);
char *synthesize_perf_probe_command(struct perf_probe_event *pev);
char *synthesize_probe_trace_command(struct probe_trace_event *tev);
char *synthesize_perf_probe_arg(struct perf_probe_arg *pa);
+char *synthesize_perf_probe_point(struct perf_probe_point *pp);
+
+int perf_probe_event__copy(struct perf_probe_event *dst,
+ struct perf_probe_event *src);

/* Check the perf_probe_event needs debuginfo */
bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 3fe6214..bb849c9 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -14,6 +14,7 @@
* GNU General Public License for more details.
*
*/
+#include <sys/uio.h>
#include "util.h"
#include "event.h"
#include "strlist.h"
@@ -324,3 +325,301 @@ int probe_file__del_events(int fd, struct strfilter *filter)

return ret;
}
+
+static void probe_cache_entry__delete(struct probe_cache_entry *node)
+{
+ if (!list_empty(&node->list))
+ list_del(&node->list);
+ if (node->tevlist)
+ strlist__delete(node->tevlist);
+ clear_perf_probe_event(&node->pev);
+ free(node->spev);
+ free(node);
+}
+
+static struct probe_cache_entry *
+probe_cache_entry__new(struct perf_probe_event *pev)
+{
+ struct probe_cache_entry *ret = zalloc(sizeof(*ret));
+
+ if (ret) {
+ INIT_LIST_HEAD(&ret->list);
+ ret->tevlist = strlist__new(NULL, NULL);
+ if (!ret->tevlist)
+ zfree(&ret);
+ if (ret && pev) {
+ ret->spev = synthesize_perf_probe_command(pev);
+ if (!ret->spev ||
+ perf_probe_event__copy(&ret->pev, pev) < 0) {
+ probe_cache_entry__delete(ret);
+ return NULL;
+ }
+ }
+ }
+
+ return ret;
+}
+
+/* For the kernel probe caches, pass target = NULL */
+static int probe_cache__open(struct probe_cache *pcache, const char *target)
+{
+ char cpath[PATH_MAX];
+ char sbuildid[SBUILD_ID_SIZE];
+ char *dir_name;
+ bool is_kallsyms = !target;
+ int ret, fd;
+
+ if (target)
+ ret = filename__sprintf_build_id(target, sbuildid);
+ else {
+ target = "[kernel.kallsyms]";
+ ret = sysfs__sprintf_build_id("/", sbuildid);
+ }
+ if (ret < 0) {
+ pr_debug("Failed to get build-id from %s.\n", target ?: "kernel");
+ return ret;
+ }
+
+ /* If we have no buildid cache, make it */
+ if (!build_id_cache__cached(sbuildid)) {
+ ret = build_id_cache__add_s(sbuildid, target,
+ is_kallsyms, NULL);
+ if (ret < 0) {
+ pr_debug("Failed to add build-id cache: %s\n", target);
+ return ret;
+ }
+ }
+
+ dir_name = build_id_cache__dirname_from_path(sbuildid, target,
+ is_kallsyms, false);
+ if (!dir_name)
+ return -ENOMEM;
+
+ snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
+ fd = open(cpath, O_CREAT | O_RDWR | O_APPEND, 0644);
+ if (fd < 0)
+ pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
+ free(dir_name);
+ pcache->fd = fd;
+
+ return fd;
+}
+
+static int probe_cache__load(struct probe_cache *pcache)
+{
+ struct probe_cache_entry *entry = NULL;
+ char buf[MAX_CMDLEN], *p;
+ int ret = 0;
+ FILE *fp;
+
+ fp = fdopen(dup(pcache->fd), "r");
+ while (!feof(fp)) {
+ if (!fgets(buf, MAX_CMDLEN, fp))
+ break;
+ p = strchr(buf, '\n');
+ if (p)
+ *p = '\0';
+ if (buf[0] == '#') { /* #perf_probe_event */
+ entry = probe_cache_entry__new(NULL);
+ entry->spev = strdup(buf + 1);
+ ret = parse_perf_probe_command(buf + 1, &entry->pev);
+ if (!entry->spev || ret < 0) {
+ probe_cache_entry__delete(entry);
+ goto out;
+ }
+ list_add_tail(&entry->list, &pcache->list);
+ } else { /* trace_probe_event */
+ if (!entry) {
+ ret = -EINVAL;
+ goto out;
+ }
+ strlist__add(entry->tevlist, buf);
+ }
+ }
+out:
+ fclose(fp);
+ return ret;
+}
+
+static struct probe_cache *probe_cache__alloc(void)
+{
+ struct probe_cache *ret = zalloc(sizeof(*ret));
+
+ if (ret) {
+ INIT_LIST_HEAD(&ret->list);
+ ret->fd = -EINVAL;
+ }
+ return ret;
+}
+
+void probe_cache__delete(struct probe_cache *pcache)
+{
+ struct probe_cache_entry *entry;
+
+ if (!pcache)
+ return;
+
+ while (!list_empty(&pcache->list)) {
+ entry = list_first_entry(&pcache->list, typeof(*entry), list);
+ probe_cache_entry__delete(entry);
+ }
+ if (pcache->fd > 0)
+ close(pcache->fd);
+ free(pcache);
+}
+
+struct probe_cache *probe_cache__new(const char *target)
+{
+ struct probe_cache *pcache = probe_cache__alloc();
+ int ret;
+
+ if (!pcache)
+ return NULL;
+
+ ret = probe_cache__open(pcache, target);
+ if (ret < 0) {
+ pr_debug("Cache open error: %d\n", ret);
+ goto out_err;
+ }
+
+ ret = probe_cache__load(pcache);
+ if (ret < 0) {
+ pr_debug("Cache read error: %d\n", ret);
+ goto out_err;
+ }
+
+ return pcache;
+
+out_err:
+ probe_cache__delete(pcache);
+ return NULL;
+}
+
+static bool streql(const char *a, const char *b)
+{
+ if (a == b)
+ return true;
+
+ if (!a || !b)
+ return false;
+
+ return !strcmp(a, b);
+}
+
+static struct probe_cache_entry *
+probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
+{
+ struct probe_cache_entry *entry = NULL;
+ char *cmd = NULL;
+
+ cmd = synthesize_perf_probe_command(pev);
+ if (!cmd)
+ return NULL;
+
+ list_for_each_entry(entry, &pcache->list, list) {
+ /* Hit if same event name or same command-string */
+ if ((pev->event &&
+ (streql(entry->pev.group, pev->group) &&
+ streql(entry->pev.event, pev->event))) ||
+ (!strcmp(entry->spev, cmd)))
+ goto found;
+ }
+ entry = NULL;
+
+found:
+ free(cmd);
+ return entry;
+}
+
+int probe_cache__add_entry(struct probe_cache *pcache,
+ struct perf_probe_event *pev,
+ struct probe_trace_event *tevs, int ntevs)
+{
+ struct probe_cache_entry *entry = NULL;
+ char *command;
+ int i, ret = 0;
+
+ if (!pcache || !pev || !tevs || ntevs <= 0) {
+ ret = -EINVAL;
+ goto out_err;
+ }
+
+ /* Remove old cache entry */
+ entry = probe_cache__find(pcache, pev);
+ if (entry)
+ probe_cache_entry__delete(entry);
+
+ ret = -ENOMEM;
+ entry = probe_cache_entry__new(pev);
+ if (!entry)
+ goto out_err;
+
+ for (i = 0; i < ntevs; i++) {
+ if (!tevs[i].point.symbol)
+ continue;
+
+ command = synthesize_probe_trace_command(&tevs[i]);
+ if (!command)
+ goto out_err;
+ strlist__add(entry->tevlist, command);
+ free(command);
+ }
+ list_add_tail(&entry->list, &pcache->list);
+ pr_debug("Added probe cache: %d\n", ntevs);
+ return 0;
+
+out_err:
+ pr_debug("Failed to add probe caches\n");
+ if (entry)
+ probe_cache_entry__delete(entry);
+ return ret;
+}
+
+static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
+{
+ struct str_node *snode;
+ struct iovec iov[3];
+ int ret;
+
+ pr_debug("Writing cache: #%s\n", entry->spev);
+ iov[0].iov_base = (void *)"#"; iov[0].iov_len = 1;
+ iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
+ iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
+ ret = writev(fd, iov, 3);
+ if (ret < 0)
+ return ret;
+
+ strlist__for_each(snode, entry->tevlist) {
+ iov[0].iov_base = (void *)snode->s;
+ iov[0].iov_len = strlen(snode->s);
+ iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
+ ret = writev(fd, iov, 2);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
+int probe_cache__commit(struct probe_cache *pcache)
+{
+ struct probe_cache_entry *entry;
+ int ret = 0;
+
+ /* TBD: if we do not update existing entries, skip it */
+ ret = lseek(pcache->fd, 0, SEEK_SET);
+ if (ret < 0)
+ goto out;
+
+ ret = ftruncate(pcache->fd, 0);
+ if (ret < 0)
+ goto out;
+
+ list_for_each_entry(entry, &pcache->list, list) {
+ ret = probe_cache_entry__write(entry, pcache->fd);
+ pr_debug("Cache committed: %d\n", ret);
+ if (ret < 0)
+ break;
+ }
+out:
+ return ret;
+}
diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
index 18ac9cf..d2b8791d 100644
--- a/tools/perf/util/probe-file.h
+++ b/tools/perf/util/probe-file.h
@@ -5,6 +5,19 @@
#include "strfilter.h"
#include "probe-event.h"

+/* Cache of probe definitions */
+struct probe_cache_entry {
+ struct list_head list;
+ struct perf_probe_event pev;
+ char *spev;
+ struct strlist *tevlist;
+};
+
+struct probe_cache {
+ int fd;
+ struct list_head list;
+};
+
#define PF_FL_UPROBE 1
#define PF_FL_RW 2

@@ -18,5 +31,11 @@ int probe_file__get_events(int fd, struct strfilter *filter,
struct strlist *plist);
int probe_file__del_strlist(int fd, struct strlist *namelist);

+struct probe_cache *probe_cache__new(const char *target);
+int probe_cache__add_entry(struct probe_cache *pcache,
+ struct perf_probe_event *pev,
+ struct probe_trace_event *tevs, int ntevs);
+int probe_cache__commit(struct probe_cache *pcache);
+void probe_cache__delete(struct probe_cache *pcache);

#endif