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-rw-r--r--trace2/tr2_tls.c193
1 files changed, 193 insertions, 0 deletions
diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
new file mode 100644
index 0000000..04900bb
--- /dev/null
+++ b/trace2/tr2_tls.c
@@ -0,0 +1,193 @@
+#include "cache.h"
+#include "thread-utils.h"
+#include "trace2/tr2_tls.h"
+
+/*
+ * Initialize size of the thread stack for nested regions.
+ * This is used to store nested region start times. Note that
+ * this stack is per-thread and not per-trace-key.
+ */
+#define TR2_REGION_NESTING_INITIAL_SIZE (100)
+
+static struct tr2tls_thread_ctx *tr2tls_thread_main;
+static uint64_t tr2tls_us_start_process;
+
+static pthread_mutex_t tr2tls_mutex;
+static pthread_key_t tr2tls_key;
+
+static int tr2_next_thread_id; /* modify under lock */
+
+void tr2tls_start_process_clock(void)
+{
+ if (tr2tls_us_start_process)
+ return;
+
+ /*
+ * Keep the absolute start time of the process (i.e. the main
+ * process) in a fixed variable since other threads need to
+ * access it. This allows them to do that without a lock on
+ * main thread's array data (because of reallocs).
+ */
+ tr2tls_us_start_process = getnanotime() / 1000;
+}
+
+struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_base_name,
+ uint64_t us_thread_start)
+{
+ struct tr2tls_thread_ctx *ctx = xcalloc(1, sizeof(*ctx));
+ struct strbuf buf = STRBUF_INIT;
+
+ /*
+ * Implicitly "tr2tls_push_self()" to capture the thread's start
+ * time in array_us_start[0]. For the main thread this gives us the
+ * application run time.
+ */
+ ctx->alloc = TR2_REGION_NESTING_INITIAL_SIZE;
+ ctx->array_us_start = (uint64_t *)xcalloc(ctx->alloc, sizeof(uint64_t));
+ ctx->array_us_start[ctx->nr_open_regions++] = us_thread_start;
+
+ ctx->thread_id = tr2tls_locked_increment(&tr2_next_thread_id);
+
+ strbuf_init(&buf, 0);
+ if (ctx->thread_id)
+ strbuf_addf(&buf, "th%02d:", ctx->thread_id);
+ strbuf_addstr(&buf, thread_base_name);
+ if (buf.len > TR2_MAX_THREAD_NAME)
+ strbuf_setlen(&buf, TR2_MAX_THREAD_NAME);
+ ctx->thread_name = strbuf_detach(&buf, NULL);
+
+ pthread_setspecific(tr2tls_key, ctx);
+
+ return ctx;
+}
+
+struct tr2tls_thread_ctx *tr2tls_get_self(void)
+{
+ struct tr2tls_thread_ctx *ctx;
+
+ if (!HAVE_THREADS)
+ return tr2tls_thread_main;
+
+ ctx = pthread_getspecific(tr2tls_key);
+
+ /*
+ * If the current thread's thread-proc did not call
+ * trace2_thread_start(), then the thread will not have any
+ * thread-local storage. Create it now and silently continue.
+ */
+ if (!ctx)
+ ctx = tr2tls_create_self("unknown", getnanotime() / 1000);
+
+ return ctx;
+}
+
+int tr2tls_is_main_thread(void)
+{
+ if (!HAVE_THREADS)
+ return 1;
+
+ return pthread_getspecific(tr2tls_key) == tr2tls_thread_main;
+}
+
+void tr2tls_unset_self(void)
+{
+ struct tr2tls_thread_ctx *ctx;
+
+ ctx = tr2tls_get_self();
+
+ pthread_setspecific(tr2tls_key, NULL);
+
+ free((char *)ctx->thread_name);
+ free(ctx->array_us_start);
+ free(ctx);
+}
+
+void tr2tls_push_self(uint64_t us_now)
+{
+ struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
+
+ ALLOC_GROW(ctx->array_us_start, ctx->nr_open_regions + 1, ctx->alloc);
+ ctx->array_us_start[ctx->nr_open_regions++] = us_now;
+}
+
+void tr2tls_pop_self(void)
+{
+ struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
+
+ if (!ctx->nr_open_regions)
+ BUG("no open regions in thread '%s'", ctx->thread_name);
+
+ ctx->nr_open_regions--;
+}
+
+void tr2tls_pop_unwind_self(void)
+{
+ struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
+
+ while (ctx->nr_open_regions > 1)
+ tr2tls_pop_self();
+}
+
+uint64_t tr2tls_region_elasped_self(uint64_t us)
+{
+ struct tr2tls_thread_ctx *ctx;
+ uint64_t us_start;
+
+ ctx = tr2tls_get_self();
+ if (!ctx->nr_open_regions)
+ return 0;
+
+ us_start = ctx->array_us_start[ctx->nr_open_regions - 1];
+
+ return us - us_start;
+}
+
+uint64_t tr2tls_absolute_elapsed(uint64_t us)
+{
+ if (!tr2tls_thread_main)
+ return 0;
+
+ return us - tr2tls_us_start_process;
+}
+
+void tr2tls_init(void)
+{
+ tr2tls_start_process_clock();
+
+ pthread_key_create(&tr2tls_key, NULL);
+ init_recursive_mutex(&tr2tls_mutex);
+
+ tr2tls_thread_main =
+ tr2tls_create_self("main", tr2tls_us_start_process);
+}
+
+void tr2tls_release(void)
+{
+ tr2tls_unset_self();
+ tr2tls_thread_main = NULL;
+
+ pthread_mutex_destroy(&tr2tls_mutex);
+ pthread_key_delete(tr2tls_key);
+}
+
+int tr2tls_locked_increment(int *p)
+{
+ int current_value;
+
+ pthread_mutex_lock(&tr2tls_mutex);
+ current_value = *p;
+ *p = current_value + 1;
+ pthread_mutex_unlock(&tr2tls_mutex);
+
+ return current_value;
+}
+
+void tr2tls_lock(void)
+{
+ pthread_mutex_lock(&tr2tls_mutex);
+}
+
+void tr2tls_unlock(void)
+{
+ pthread_mutex_unlock(&tr2tls_mutex);
+}