#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+#include <lttng/ust-clock.h>
+
#include "lttng-ust-uuid.h"
-/* 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);
+};
-/*
- * Currently using the kernel MONOTONIC clock, waiting for kernel-side
- * LTTng to implement mmap'd trace clock.
- */
+extern struct lttng_trace_clock *lttng_trace_clock;
-/* Choosing correct trace clock */
+void lttng_ust_clock_init(void);
+
+/* Use the kernel MONOTONIC clock. */
static __inline__
-uint64_t trace_clock_read64(void)
+uint64_t trace_clock_read64_monotonic(void)
{
struct timespec ts;
- clock_gettime(CLOCK_MONOTONIC, &ts);
+ 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(void)
-{
- return 1000000000ULL;
-}
-
-static __inline__
-const int trace_clock_uuid(char *uuid)
+uint64_t trace_clock_read64(void)
{
- int ret = 0;
- size_t len;
- FILE *fp;
+ struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
- /*
- * 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;
+ if (caa_likely(!ltc)) {
+ return trace_clock_read64_monotonic();
+ } else {
+ cmm_read_barrier_depends(); /* load ltc before content */
+ return ltc->read64();
}
- uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0';
-end:
- fclose(fp);
- return ret;
}
#endif /* _UST_CLOCK_H */