gettime: improve cpu clock test

[fio.git] / gettime.c

diff --git a/gettime.c b/gettime.c
index 1cbef84b0d765f224309214067fa92f1048c7fed..c256a96c16c8f26253a253c82d23d23f4a5d914c 100644 (file)
--- a/gettime.c
+++ b/gettime.c
@@ -548,7 +548,7 @@ uint64_t time_since_now(const struct timespec *s)
 }
 
 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK)  && \
-    defined(CONFIG_SFAA)
+    defined(CONFIG_SYNC_SYNC) && defined(CONFIG_CMP_SWAP)
 
 #define CLOCK_ENTRIES_DEBUG    100000
 #define CLOCK_ENTRIES_TEST     1000
@@ -570,9 +570,10 @@ struct clock_thread {
        struct clock_entry *entries;
 };
 
-static inline uint32_t atomic32_inc_return(uint32_t *seq)
+static inline uint32_t atomic32_compare_and_swap(uint32_t *ptr, uint32_t old,
+                                                uint32_t new)
 {
-       return 1 + __sync_fetch_and_add(seq, 1);
+       return __sync_val_compare_and_swap(ptr, old, new);
 }
 
 static void *clock_thread_fn(void *data)
@@ -580,7 +581,6 @@ static void *clock_thread_fn(void *data)
        struct clock_thread *t = data;
        struct clock_entry *c;
        os_cpu_mask_t cpu_mask;
-       uint32_t last_seq;
        unsigned long long first;
        int i;
 
@@ -604,7 +604,6 @@ static void *clock_thread_fn(void *data)
        pthread_mutex_unlock(&t->started);
 
        first = get_cpu_clock();
-       last_seq = 0;
        c = &t->entries[0];
        for (i = 0; i < t->nr_entries; i++, c++) {
                uint32_t seq;
@@ -612,11 +611,15 @@ static void *clock_thread_fn(void *data)
 
                c->cpu = t->cpu;
                do {
-                       seq = atomic32_inc_return(t->seq);
-                       if (seq < last_seq)
+                       seq = *t->seq;
+                       if (seq == UINT_MAX)
                                break;
+                       __sync_synchronize();
                        tsc = get_cpu_clock();
-               } while (seq != *t->seq);
+               } while (seq != atomic32_compare_and_swap(t->seq, seq, seq + 1));
+
+               if (seq == UINT_MAX)
+                       break;
 
                c->seq = seq;
                c->tsc = tsc;
@@ -634,7 +637,7 @@ static void *clock_thread_fn(void *data)
         * The most common platform clock breakage is returning zero
         * indefinitely. Check for that and return failure.
         */
-       if (!t->entries[i - 1].tsc && !t->entries[0].tsc)
+       if (i > 1 && !t->entries[i - 1].tsc && !t->entries[0].tsc)
                goto err;
 
        fio_cpuset_exit(&cpu_mask);