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42 #include <sys/queue.h>
46 #include <rte_common.h>
48 #include <rte_cycles.h>
49 #include <rte_tailq.h>
50 #include <rte_memory.h>
51 #include <rte_memzone.h>
53 #include <rte_debug.h>
55 #include "eal_private.h"
56 #include "eal_internal_cfg.h"
58 enum timer_source eal_timer_source = EAL_TIMER_HPET;
60 /* The frequency of the RDTSC timer resolution */
61 static uint64_t eal_tsc_resolution_hz = 0;
63 #ifdef RTE_LIBEAL_USE_HPET
65 #define DEV_HPET "/dev/hpet"
67 /* Maximum number of counters. */
68 #define HPET_TIMER_NUM 3
70 /* General capabilities register */
71 #define CLK_PERIOD_SHIFT 32 /* Clock period shift. */
72 #define CLK_PERIOD_MASK 0xffffffff00000000ULL /* Clock period mask. */
73 #define COUNT_SIZE_CAP_SHIFT 13 /* Count size capa. shift. */
74 #define COUNT_SIZE_CAP_MASK 0x0000000000002000ULL /* Count size capa. mask. */
77 * HPET timer registers. From the Intel IA-PC HPET (High Precision Event
78 * Timers) Specification.
80 struct eal_hpet_regs {
81 /* Memory-mapped, software visible registers */
82 uint64_t capabilities; /**< RO General Capabilities Register. */
83 uint64_t reserved0; /**< Reserved for future use. */
84 uint64_t config; /**< RW General Configuration Register. */
85 uint64_t reserved1; /**< Reserved for future use. */
86 uint64_t isr; /**< RW Clear General Interrupt Status. */
87 uint64_t reserved2[25]; /**< Reserved for future use. */
89 uint64_t counter; /**< RW Main Counter Value Register. */
91 uint32_t counter_l; /**< RW Main Counter Low. */
92 uint32_t counter_h; /**< RW Main Counter High. */
95 uint64_t reserved3; /**< Reserved for future use. */
97 uint64_t config; /**< RW Timer Config and Capability Reg. */
98 uint64_t comp; /**< RW Timer Comparator Value Register. */
99 uint64_t fsb; /**< RW FSB Interrupt Route Register. */
100 uint64_t reserved4; /**< Reserved for future use. */
101 } timers[HPET_TIMER_NUM]; /**< Set of HPET timers. */
104 /* Mmap'd hpet registers */
105 static volatile struct eal_hpet_regs *eal_hpet = NULL;
107 /* Period at which the HPET counter increments in
108 * femtoseconds (10^-15 seconds). */
109 static uint32_t eal_hpet_resolution_fs = 0;
111 /* Frequency of the HPET counter in Hz */
112 static uint64_t eal_hpet_resolution_hz = 0;
114 /* Incremented 4 times during one 32bits hpet full count */
115 static uint32_t eal_hpet_msb;
117 static pthread_t msb_inc_thread_id;
120 * This function runs on a specific thread to update a global variable
121 * containing used to process MSB of the HPET (unfortunatelly, we need
122 * this because hpet is 32 bits by default under linux).
125 hpet_msb_inc(__attribute__((unused)) void *arg)
130 t = (eal_hpet->counter_l >> 30);
131 if (t != (eal_hpet_msb & 3))
138 rte_get_hpet_hz(void)
140 if(internal_config.no_hpet)
141 rte_panic("Error, HPET called, but no HPET present\n");
143 return eal_hpet_resolution_hz;
147 rte_get_hpet_cycles(void)
152 if(internal_config.no_hpet)
153 rte_panic("Error, HPET called, but no HPET present\n");
155 t = eal_hpet->counter_l;
157 ret = (msb + 2 - (t >> 30)) / 4;
167 rte_delay_us(unsigned us)
169 const uint64_t start = rte_get_timer_cycles();
170 const uint64_t ticks = (uint64_t)us * rte_get_timer_hz() / 1E6;
171 while ((rte_get_timer_cycles() - start) < ticks)
178 return eal_tsc_resolution_hz;
182 #ifdef RTE_LIBEAL_USE_HPET
184 * Open and mmap /dev/hpet (high precision event timer) that will
185 * provide our time reference.
188 rte_eal_hpet_init(int make_default)
192 if (internal_config.no_hpet) {
193 RTE_LOG(INFO, EAL, "HPET is disabled\n");
197 fd = open(DEV_HPET, O_RDONLY);
199 RTE_LOG(ERR, EAL, "ERROR: Cannot open "DEV_HPET": %s!\n",
201 internal_config.no_hpet = 1;
204 eal_hpet = mmap(NULL, 1024, PROT_READ, MAP_SHARED, fd, 0);
205 if (eal_hpet == MAP_FAILED) {
206 RTE_LOG(ERR, EAL, "ERROR: Cannot mmap "DEV_HPET"!\n"
207 "Please enable CONFIG_HPET_MMAP in your kernel configuration "
208 "to allow HPET support.\n"
209 "To run without using HPET, set CONFIG_RTE_LIBEAL_USE_HPET=n "
210 "in your build configuration or use '--no-hpet' EAL flag.\n");
212 internal_config.no_hpet = 1;
217 eal_hpet_resolution_fs = (uint32_t)((eal_hpet->capabilities &
221 eal_hpet_resolution_hz = (1000ULL*1000ULL*1000ULL*1000ULL*1000ULL) /
222 (uint64_t)eal_hpet_resolution_fs;
224 RTE_LOG(INFO, EAL, "HPET frequency is ~%"PRIu64" kHz\n",
225 eal_hpet_resolution_hz/1000);
227 eal_hpet_msb = (eal_hpet->counter_l >> 30);
229 /* create a thread that will increment a global variable for
230 * msb (hpet is 32 bits by default under linux) */
231 ret = pthread_create(&msb_inc_thread_id, NULL,
232 (void *(*)(void *))hpet_msb_inc, NULL);
234 RTE_LOG(ERR, EAL, "ERROR: Cannot create HPET timer thread!\n");
235 internal_config.no_hpet = 1;
240 eal_timer_source = EAL_TIMER_HPET;
246 set_tsc_freq_from_clock(void)
248 #ifdef CLOCK_MONOTONIC_RAW
249 #define NS_PER_SEC 1E9
251 struct timespec sleeptime = {.tv_nsec = 5E8 }; /* 1/2 second */
253 struct timespec t_start, t_end;
255 if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
256 uint64_t ns, end, start = rte_rdtsc();
257 nanosleep(&sleeptime,NULL);
258 clock_gettime(CLOCK_MONOTONIC_RAW, &t_end);
260 ns = ((t_end.tv_sec - t_start.tv_sec) * NS_PER_SEC);
261 ns += (t_end.tv_nsec - t_start.tv_nsec);
263 double secs = (double)ns/NS_PER_SEC;
264 eal_tsc_resolution_hz = (uint64_t)((end - start)/secs);
272 set_tsc_freq_fallback(void)
274 RTE_LOG(WARNING, EAL, "WARNING: clock_gettime cannot use "
275 "CLOCK_MONOTONIC_RAW and HPET is not available"
276 " - clock timings may be less accurate.\n");
277 /* assume that the sleep(1) will sleep for 1 second */
278 uint64_t start = rte_rdtsc();
280 eal_tsc_resolution_hz = rte_rdtsc() - start;
283 * This function measures the TSC frequency. It uses a variety of approaches.
285 * 1. If kernel provides CLOCK_MONOTONIC_RAW we use that to tune the TSC value
286 * 2. If kernel does not provide that, and we have HPET support, tune using HPET
287 * 3. Lastly, if neither of the above can be used, just sleep for 1 second and
288 * tune off that, printing a warning about inaccuracy of timing
293 if (set_tsc_freq_from_clock() < 0)
294 set_tsc_freq_fallback();
296 RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
297 eal_tsc_resolution_hz/1000);
301 rte_eal_timer_init(void)
304 eal_timer_source = EAL_TIMER_TSC;