From: Tzvetomir Stoyanov <tstoyanov@vmware.com>
To: "rostedt@goodmis.org" <rostedt@goodmis.org>
Cc: "linux-trace-devel@vger.kernel.org" <linux-trace-devel@vger.kernel.org>
Subject: [PATCH v3] tools/lib/traceevent: make libtraceevent thread safe
Date: Wed, 28 Nov 2018 13:31:31 +0000 [thread overview]
Message-ID: <20181128133119.13149-1-tstoyanov@vmware.com> (raw)
This patch is a PoC about transforming libtraceevent
into a thread safe library. It implements per thread local
storage and internal APIs to access it. It covers only
tep->last_event cache, but easily can be extended with all
library's thread sensitive data.
Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
v2: Added local thread data per tep context
v3: Implemented APIs to access specific tread local data,
instead of the whole struct tep_thread_data.
---
tools/lib/traceevent/event-parse-local.h | 18 ++-
tools/lib/traceevent/event-parse-thread.c | 131 ++++++++++++++++++++++
tools/lib/traceevent/event-parse.c | 21 ++--
3 files changed, 158 insertions(+), 12 deletions(-)
create mode 100644 tools/lib/traceevent/event-parse-thread.c
diff --git a/tools/lib/traceevent/event-parse-local.h b/tools/lib/traceevent/event-parse-local.h
index 9a092dd4a86d..aa9418fdefd0 100644
--- a/tools/lib/traceevent/event-parse-local.h
+++ b/tools/lib/traceevent/event-parse-local.h
@@ -14,6 +14,14 @@ struct func_list;
struct event_handler;
struct func_resolver;
+/* cache */
+struct tep_thread_data {
+ struct tep_handle *tep;
+ struct tep_thread_data *next;
+
+ struct tep_event *last_event;
+};
+
struct tep_handle {
int ref_count;
@@ -83,9 +91,6 @@ struct tep_handle {
struct event_handler *handlers;
struct tep_function_handler *func_handlers;
- /* cache */
- struct tep_event *last_event;
-
char *trace_clock;
};
@@ -96,4 +101,11 @@ unsigned short tep_data2host2(struct tep_handle *pevent, unsigned short data);
unsigned int tep_data2host4(struct tep_handle *pevent, unsigned int data);
unsigned long long tep_data2host8(struct tep_handle *pevent, unsigned long long data);
+/* tep cache per thread */
+struct tep_event *tep_find_event_by_id_cache(struct tep_handle *tep, int id);
+struct tep_event *
+tep_find_event_by_name_cache(struct tep_handle *tep, const char *name, const char *sys);
+void tep_set_serach_event_cache(struct tep_handle *tep, struct tep_event *event);
+void tep_destroy_thread_local(struct tep_handle *tep);
+
#endif /* _PARSE_EVENTS_INT_H */
diff --git a/tools/lib/traceevent/event-parse-thread.c b/tools/lib/traceevent/event-parse-thread.c
new file mode 100644
index 000000000000..84707c24ac6b
--- /dev/null
+++ b/tools/lib/traceevent/event-parse-thread.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+
+#include "event-parse.h"
+#include "event-parse-local.h"
+#include "event-utils.h"
+
+static __thread struct tep_thread_data *tep_thread_local;
+
+static struct tep_thread_data *tep_alloc_thread_local(struct tep_handle *tep)
+{
+ struct tep_thread_data *local;
+
+ local = calloc(1, sizeof(struct tep_thread_data));
+ if (local) {
+ local->tep = tep;
+ local->next = tep_thread_local;
+ tep_thread_local = local;
+ }
+ return local;
+}
+
+static struct tep_thread_data *tep_get_thread_local(struct tep_handle *tep)
+{
+ struct tep_thread_data *local;
+ static __thread struct tep_thread_data *last_local;
+
+ if (last_local && last_local->tep == tep)
+ return last_local;
+
+ local = tep_thread_local;
+ while (local) {
+ if (local->tep == tep) {
+ last_local = local;
+ return local;
+ }
+ local = local->next;
+ }
+
+ return NULL;
+}
+
+/**
+ * tep_find_event_by_id_cache - Find event with given id in the cache
+ * @tep: a handle to the tep context
+ * @id: event's id
+ *
+ * Searches in the cache for event with given id
+ */
+struct tep_event *tep_find_event_by_id_cache(struct tep_handle *tep, int id)
+{
+ struct tep_thread_data *local = tep_get_thread_local(tep);
+
+ if (local && local->last_event && local->last_event->id == id)
+ return local->last_event;
+
+ return NULL;
+}
+
+/**
+ * tep_find_event_by_name_cache - Find event with given name and sys in the cache
+ * @tep: a handle to the tep context
+ * @name: event's name
+ * @sys: event's system
+ *
+ * Searches in the cache for event with given name and system
+ */
+struct tep_event *
+tep_find_event_by_name_cache(struct tep_handle *tep, const char *name, const char *sys)
+{
+ struct tep_thread_data *local = tep_get_thread_local(tep);
+
+ if (local && local->last_event &&
+ strcmp(local->last_event->name, name) == 0 &&
+ (!sys || strcmp(local->last_event->system, sys) == 0))
+ return local->last_event;
+
+ return NULL;
+}
+
+/**
+ * tep_set_serach_event_cache - set last used event in the cache
+ * @tep: a handle to the tep context
+ * @event: pointer to the last used event
+ *
+ * Sets last used event in the cache, to speed up the next searches
+ */
+void tep_set_serach_event_cache(struct tep_handle *tep, struct tep_event *event)
+{
+ struct tep_thread_data *local = tep_get_thread_local(tep);
+
+ if (!local)
+ local = tep_alloc_thread_local(tep);
+
+ if (local)
+ local->last_event = event;
+}
+
+/**
+ * tep_destroy_thread_local - destroy local data of tep context
+ * @tep: a handle to the tep context
+ *
+ * Destroys local data of tep context for the current thread
+ */
+void tep_destroy_thread_local(struct tep_handle *tep)
+{
+ struct tep_thread_data **local, *del;
+
+ if (!tep_thread_local)
+ return;
+ local = &tep_thread_local;
+
+ while (*local) {
+ if ((*local)->tep == tep) {
+ tep_thread_local = (*local)->next;
+ free(*local);
+ return;
+ }
+ if ((*local)->next && (*local)->next->tep == tep) {
+ del = (*local)->next;
+ (*local)->next = (*local)->next->next;
+ free(del);
+ return;
+ }
+ local = &((*local)->next);
+ }
+}
+
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index a5048c1b9bec..8fd727023640 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3485,10 +3485,11 @@ struct tep_event *tep_find_event(struct tep_handle *pevent, int id)
struct tep_event **eventptr;
struct tep_event key;
struct tep_event *pkey = &key;
+ struct tep_event *event_cache = tep_find_event_by_id_cache(pevent, id);
/* Check cache first */
- if (pevent->last_event && pevent->last_event->id == id)
- return pevent->last_event;
+ if (event_cache)
+ return event_cache;
key.id = id;
@@ -3496,7 +3497,7 @@ struct tep_event *tep_find_event(struct tep_handle *pevent, int id)
sizeof(*pevent->events), events_id_cmp);
if (eventptr) {
- pevent->last_event = *eventptr;
+ tep_set_serach_event_cache(pevent, *eventptr);
return *eventptr;
}
@@ -3516,13 +3517,13 @@ struct tep_event *
tep_find_event_by_name(struct tep_handle *pevent,
const char *sys, const char *name)
{
- struct tep_event *event = NULL;
int i;
+ struct tep_event *event = NULL;
+ struct tep_event *event_cache = tep_find_event_by_name_cache(pevent, name, sys);
- if (pevent->last_event &&
- strcmp(pevent->last_event->name, name) == 0 &&
- (!sys || strcmp(pevent->last_event->system, sys) == 0))
- return pevent->last_event;
+ /* Check cache first */
+ if (event_cache)
+ return event_cache;
for (i = 0; i < pevent->nr_events; i++) {
event = pevent->events[i];
@@ -3533,10 +3534,12 @@ tep_find_event_by_name(struct tep_handle *pevent,
break;
}
}
+
if (i == pevent->nr_events)
event = NULL;
+ if (event)
+ tep_set_serach_event_cache(pevent, event);
- pevent->last_event = event;
return event;
}
--
2.19.1
next reply other threads:[~2018-11-29 0:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 13:31 Tzvetomir Stoyanov [this message]
2018-11-28 14:27 ` [PATCH v3] tools/lib/traceevent: make libtraceevent thread safe Steven Rostedt
2018-11-28 14:50 ` Tzvetomir Stoyanov
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