Cleanup: clock description for metadata was moved to lttng-sessiond

[lttng-ust.git] / liblttng-ust / clock.h

diff --git a/liblttng-ust/clock.h b/liblttng-ust/clock.h
index 82a7b45cd5294a3f35c63e172ea8105d0e5c2e0d..d5548e90e4fe9a301f06fd6dc86ad400c80ff091 100644 (file)
--- a/liblttng-ust/clock.h
+++ b/liblttng-ust/clock.h
@@ -25,61 +25,49 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <urcu/system.h>
+#include <urcu/arch.h>
+#include <lttng/ust-clock.h>
 
-/*
- * Includes final \0.
- */
-#define CLOCK_UUID_LEN         37
+#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, CLOCK_UUID_LEN - 1, fp);
-       if (len < CLOCK_UUID_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[CLOCK_UUID_LEN - 1] = '\0';
-end:
-       fclose(fp);
-       return ret;
 }
 
 #endif /* _UST_CLOCK_H */