pre_read fixes
[fio.git] / gettime.c
1 /*
2  * Clock functions
3  */
4
5 #include <unistd.h>
6 #include <sys/time.h>
7
8 #include "fio.h"
9 #include "smalloc.h"
10
11 #include "hash.h"
12
13 static int clock_gettime_works;
14 static struct timeval last_tv;
15 static int last_tv_valid;
16
17 static struct timeval *fio_tv;
18 int fio_gtod_offload = 0;
19 int fio_gtod_cpu = -1;
20
21 #ifdef FIO_DEBUG_TIME
22
23 #define HASH_BITS       8
24 #define HASH_SIZE       (1 << HASH_BITS)
25
26 static struct flist_head hash[HASH_SIZE];
27 static int gtod_inited;
28
29 struct gtod_log {
30         struct flist_head list;
31         void *caller;
32         unsigned long calls;
33 };
34
35 static struct gtod_log *find_hash(void *caller)
36 {
37         unsigned long h = hash_ptr(caller, HASH_BITS);
38         struct flist_head *entry;
39
40         flist_for_each(entry, &hash[h]) {
41                 struct gtod_log *log = flist_entry(entry, struct gtod_log,
42                                                                         list);
43
44                 if (log->caller == caller)
45                         return log;
46         }
47
48         return NULL;
49 }
50
51 static struct gtod_log *find_log(void *caller)
52 {
53         struct gtod_log *log = find_hash(caller);
54
55         if (!log) {
56                 unsigned long h;
57
58                 log = malloc(sizeof(*log));
59                 INIT_FLIST_HEAD(&log->list);
60                 log->caller = caller;
61                 log->calls = 0;
62
63                 h = hash_ptr(caller, HASH_BITS);
64                 flist_add_tail(&log->list, &hash[h]);
65         }
66
67         return log;
68 }
69
70 static void gtod_log_caller(void *caller)
71 {
72         if (gtod_inited) {
73                 struct gtod_log *log = find_log(caller);
74
75                 log->calls++;
76         }
77 }
78
79 static void fio_exit fio_dump_gtod(void)
80 {
81         unsigned long total_calls = 0;
82         int i;
83
84         for (i = 0; i < HASH_SIZE; i++) {
85                 struct flist_head *entry;
86                 struct gtod_log *log;
87
88                 flist_for_each(entry, &hash[i]) {
89                         log = flist_entry(entry, struct gtod_log, list);
90
91                         printf("function %p, calls %lu\n", log->caller,
92                                                                 log->calls);
93                         total_calls += log->calls;
94                 }
95         }
96
97         printf("Total %lu gettimeofday\n", total_calls);
98 }
99
100 static void fio_init gtod_init(void)
101 {
102         int i;
103
104         for (i = 0; i < HASH_SIZE; i++)
105                 INIT_FLIST_HEAD(&hash[i]);
106
107         gtod_inited = 1;
108 }
109
110 #endif /* FIO_DEBUG_TIME */
111
112 #ifdef FIO_DEBUG_TIME
113 void fio_gettime(struct timeval *tp, void *caller)
114 #else
115 void fio_gettime(struct timeval *tp, void fio_unused *caller)
116 #endif
117 {
118 #ifdef FIO_DEBUG_TIME
119         if (!caller)
120                 caller = __builtin_return_address(0);
121
122         gtod_log_caller(caller);
123 #endif
124         if (fio_tv) {
125                 memcpy(tp, fio_tv, sizeof(*tp));
126                 return;
127         } else if (!clock_gettime_works) {
128 gtod:
129                 gettimeofday(tp, NULL);
130         } else {
131                 struct timespec ts;
132
133                 if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
134                         clock_gettime_works = 0;
135                         goto gtod;
136                 }
137
138                 tp->tv_sec = ts.tv_sec;
139                 tp->tv_usec = ts.tv_nsec / 1000;
140         }
141
142         /*
143          * If Linux is using the tsc clock on non-synced processors,
144          * sometimes time can appear to drift backwards. Fix that up.
145          */
146         if (last_tv_valid) {
147                 if (tp->tv_sec < last_tv.tv_sec)
148                         tp->tv_sec = last_tv.tv_sec;
149                 else if (last_tv.tv_sec == tp->tv_sec &&
150                          tp->tv_usec < last_tv.tv_usec)
151                         tp->tv_usec = last_tv.tv_usec;
152         }
153         last_tv_valid = 1;
154         memcpy(&last_tv, tp, sizeof(*tp));
155 }
156
157 void fio_gtod_init(void)
158 {
159         fio_tv = smalloc(sizeof(struct timeval));
160         assert(fio_tv);
161 }
162
163 void fio_gtod_update(void)
164 {
165         gettimeofday(fio_tv, NULL);
166 }