Changeset cc36562b in mainline for uspace/lib/c/generic/time.c

Timestamp:

2018-08-25T19:06:27Z (7 years ago)

Author:

Jakub Jermar <jakub@…>

Children:

72df613

Parents:

02f547f

Message:

Provide a single clock() implementation in libc

Also attempt to fix the implementation to return microseconds (clocks)
rather than processor cycles.

File:

• uspace/lib/c/generic/time.c (modified) (2 diffs)

uspace/lib/c/generic/time.c

@@ -50 +50 @@
 #include <loc.h>
 #include <device/clock_dev.h>
+#include <stats.h>
 
 #define ASCTIME_BUF_LEN  26
@@ -70 +71 @@
 static async_sess_t *clock_conn = NULL;
 
-/** Return processor time used by the program.
- *
- * @return -1  The processor time used is not available in this implementation.
+/**
+ * Get CPU time used since the process invocation.
+ *
+ * @return Consumed microseconds by this process or -1 if not available.
  */
 clock_t clock(void)
 {
-        return (clock_t) -1;
+        static_assert(CLOCKS_PER_SEC == 1000000);
+
+        size_t count;
+        stats_cpu_t *cpu_stats = stats_get_cpus(&count);
+        if (!cpu_stats)
+                return (clock_t) -1;
+
+        clock_t total_usecs = -1;
+        if (cpu_stats) {
+                stats_task_t *task_stats = stats_get_task(task_get_id());
+                if (task_stats) {
+                        total_usecs = (clock_t) (task_stats->kcycles +
+                            task_stats->ucycles) / cpu_stats->frequency_mhz;
+                        free(task_stats);
+                }
+                free(cpu_stats);
+        }
+
+        return total_usecs;
 }