#include <sys/time.h>
#include <stdint.h>
#include <stddef.h>
-#include <lttng/core.h>
+#include <stdio.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+#include <lttng/ust-clock.h>
-/* TRACE CLOCK */
+#include "lttng-ust-uuid.h"
-/*
- * Currently using the kernel MONOTONIC clock, waiting for kernel-side
- * LTTng to implement mmap'd trace clock.
- */
+struct lttng_trace_clock {
+ uint64_t (*read64)(void);
+ uint64_t (*freq)(void);
+ int (*uuid)(char *uuid);
+ const char *(*name)(void);
+ const char *(*description)(void);
+};
+
+extern struct lttng_trace_clock *lttng_trace_clock;
+
+void lttng_ust_clock_init(void);
-/* Choosing correct trace clock */
+/* Use the kernel MONOTONIC clock. */
-static __inline__ uint64_t trace_clock_read64(void)
+static __inline__
+uint64_t trace_clock_read64_monotonic(void)
{
struct timespec ts;
- clock_gettime(CLOCK_MONOTONIC, &ts);
- return (ts.tv_sec * 1000000000) + ts.tv_nsec;
+ if (caa_unlikely(clock_gettime(CLOCK_MONOTONIC, &ts))) {
+ ts.tv_sec = 0;
+ ts.tv_nsec = 0;
+ }
+ return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec;
+}
+
+static __inline__
+uint64_t trace_clock_freq_monotonic(void)
+{
+ return 1000000000ULL;
+}
+
+static __inline__
+int trace_clock_uuid_monotonic(char *uuid)
+{
+ int ret = 0;
+ size_t len;
+ FILE *fp;
+
+ /*
+ * boot_id needs to be read once before being used concurrently
+ * to deal with a Linux kernel race. A fix is proposed for
+ * upstream, but the work-around is needed for older kernels.
+ */
+ fp = fopen("/proc/sys/kernel/random/boot_id", "r");
+ if (!fp) {
+ return -ENOENT;
+ }
+ len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp);
+ if (len < LTTNG_UST_UUID_STR_LEN - 1) {
+ ret = -EINVAL;
+ goto end;
+ }
+ uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0';
+end:
+ fclose(fp);
+ return ret;
+}
+
+static __inline__
+const char *trace_clock_name_monotonic(void)
+{
+ return "monotonic";
}
-#if __i386__ || __x86_64__
-static __inline__ uint64_t trace_clock_frequency(void)
+static __inline__
+const char *trace_clock_description_monotonic(void)
{
- return 1000000000LL;
+ return "Monotonic Clock";
}
-#endif /* #else #if __i386__ || __x86_64__ */
-static __inline__ uint32_t trace_clock_freq_scale(void)
+static __inline__
+uint64_t trace_clock_read64(void)
{
- return 1;
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+ if (caa_likely(!ltc)) {
+ return trace_clock_read64_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->read64();
+ }
+}
+
+static __inline__
+uint64_t trace_clock_freq(void)
+{
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_freq_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->freq();
+ }
+}
+
+static __inline__
+int trace_clock_uuid(char *uuid)
+{
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+ cmm_read_barrier_depends(); /* load ltc before content */
+ /* Use default UUID cb when NULL */
+ if (!ltc || !ltc->uuid) {
+ return trace_clock_uuid_monotonic(uuid);
+ } else {
+ return ltc->uuid(uuid);
+ }
+}
+
+static __inline__
+const char *trace_clock_name(void)
+{
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_name_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->name();
+ }
+}
+
+static __inline__
+const char *trace_clock_description(void)
+{
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
+
+ if (!ltc) {
+ return trace_clock_description_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->description();
+ }
}
#endif /* _UST_CLOCK_H */