Create an instance of btf for each worker thread, and add type info to
the local btf instance in the steal-function of pahole without mutex
acquiring. Once finished with all worker threads, merge all
per-thread btf instances to the primary btf instance.
Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxx>
---
btf_encoder.c | 5 ++
btf_encoder.h | 2 +
pahole.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 124 insertions(+), 8 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index 9d015f304e92..56a76f5d7275 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -1529,3 +1529,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
out:
return err;
}
+
+struct btf *btf_encoder__btf(struct btf_encoder *encoder)
+{
+ return encoder->btf;
+}
diff --git a/btf_encoder.h b/btf_encoder.h
index f133b0d7674d..0f0eee84df74 100644
--- a/btf_encoder.h
+++ b/btf_encoder.h
@@ -29,4 +29,6 @@ struct btf_encoder *btf_encoders__first(struct list_head *encoders);
struct btf_encoder *btf_encoders__next(struct btf_encoder *encoder);
+struct btf *btf_encoder__btf(struct btf_encoder *encoder);
+
#endif /* _BTF_ENCODER_H_ */
diff --git a/pahole.c b/pahole.c
index f3eeaaca4cdf..8dcd6bf951fe 100644
--- a/pahole.c
+++ b/pahole.c
@@ -2798,6 +2798,72 @@ out:
static struct type_instance *header;
+struct thread_data {
+ struct btf *btf;
+ struct btf_encoder *encoder;
+};
+
+static int pahole_threads_prepare(struct conf_load *conf, int nr_threads, void **thr_data)
+{
+ int i;
+ struct thread_data *threads = calloc(sizeof(struct thread_data), nr_threads);
+
+ for (i = 0; i < nr_threads; i++)
+ thr_data[i] = threads + i;
+
+ return 0;
+}
+
+static int pahole_thread_exit(struct conf_load *conf, void *thr_data)
+{
+ struct thread_data *thread = thr_data;
+
+ if (thread == NULL)
+ return 0;
+
+ /*
+ * Here we will call btf__dedup() here once we extend
+ * btf__dedup().
+ */
+
+ return 0;
+}
+
+static int pahole_threads_collect(struct conf_load *conf, int nr_threads, void **thr_data,
+ int error)
+{
+ struct thread_data **threads = (struct thread_data **)thr_data;
+ int i;
+ int err = 0;
+
+ if (error)
+ goto out;
+
+ for (i = 0; i < nr_threads; i++) {
+ /*
+ * Merge content of the btf instances of worker threads to the btf
+ * instance of the primary btf_encoder.
+ */
+ if (!threads[i]->btf || threads[i]->encoder == btf_encoder)
+ continue; /* The primary btf_encoder */
+ err = btf__add_btf(btf_encoder__btf(btf_encoder), threads[i]->btf);
+ if (err < 0)
+ goto out;
+ btf_encoder__delete(threads[i]->encoder);
+ threads[i]->encoder = NULL;
+ }
+ err = 0;
+
+out:
+ for (i = 0; i < nr_threads; i++) {
+ if (threads[i]->encoder && threads[i]->encoder != btf_encoder)
+ btf_encoder__delete(threads[i]->encoder);
+ }
+ free(threads[0]);
+
+ return err;
+}
+
static enum load_steal_kind pahole_stealer(struct cu *cu,
struct conf_load *conf_load,
void *thr_data)
@@ -2819,30 +2885,70 @@ static enum load_steal_kind pahole_stealer(struct cu *cu,
if (btf_encode) {
static pthread_mutex_t btf_lock = PTHREAD_MUTEX_INITIALIZER;
+ struct btf_encoder *encoder;
- pthread_mutex_lock(&btf_lock);
/*
* FIXME:
*
* This should be really done at main(), but since in the current codebase only at this
* point we'll have cu->elf setup...
*/
+ pthread_mutex_lock(&btf_lock);
if (!btf_encoder) {
- btf_encoder = btf_encoder__new(cu, detached_btf_filename, conf_load->base_btf, skip_encoding_btf_vars,
- btf_encode_force, btf_gen_floats, global_verbose);
- if (btf_encoder == NULL) {
- ret = LSK__STOP_LOADING;
- goto out_btf;
+ /*
+ * btf_encoder is the primary encoder.
+ * And, it is used by the thread
+ * create it.
+ */
+ btf_encoder = btf_encoder__new(cu, detached_btf_filename,
+ conf_load->base_btf,
+ skip_encoding_btf_vars,
+ btf_encode_force,
+ btf_gen_floats, global_verbose);
+ if (btf_encoder && thr_data) {
+ struct thread_data *thread = thr_data;
+
+ thread->encoder = btf_encoder;
+ thread->btf = btf_encoder__btf(btf_encoder);
}
}
+ pthread_mutex_unlock(&btf_lock);
+
+ if (btf_encoder == NULL) {
+ ret = LSK__STOP_LOADING;
+ goto out_btf;
+ }
- if (btf_encoder__encode_cu(btf_encoder, cu)) {
+ /*
+ * thr_data keeps per-thread data for worker threads. Each worker thread
+ * has an encoder. The main thread will merge the data collected by all
+ * these encoders to btf_encoder. However, the first thread reaching this
+ * function creates btf_encoder and reuses it as its local encoder. It
+ * avoids copying the data collected by the first thread.
+ */
+ if (thr_data) {
+ struct thread_data *thread = (struct thread_data *)thr_data;
+
+ if (thread->encoder == NULL) {
+ thread->encoder =
+ btf_encoder__new(cu, detached_btf_filename,
+ NULL,
+ skip_encoding_btf_vars,
+ btf_encode_force,
+ btf_gen_floats,
+ global_verbose);
+ thread->btf = btf_encoder__btf(thread->encoder);
+ }
+ encoder = thread->encoder;
+ } else
+ encoder = btf_encoder;
+
+ if (btf_encoder__encode_cu(encoder, cu)) {
fprintf(stderr, "Encountered error while encoding BTF.\n");
exit(1);
}
ret = LSK__DELETE;
out_btf:
- pthread_mutex_unlock(&btf_lock);
return ret;
}
#if 0
@@ -3207,6 +3313,9 @@ int main(int argc, char *argv[])
memset(tab, ' ', sizeof(tab) - 1);
conf_load.steal = pahole_stealer;
+ conf_load.thread_exit = pahole_thread_exit;
+ conf_load.threads_prepare = pahole_threads_prepare;
+ conf_load.threads_collect = pahole_threads_collect;
// Make 'pahole --header type < file' a shorter form of 'pahole -C type --count 1 < file'
if (conf.header_type && !class_name && prettify_input) {
--
2.30.2
