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timer: get TSC frequency from /proc/cpuinfo

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Frequency was guessed by sleeping 1 sec.
Now, read frequency from cpuinfo first.
Keep sleep method as fallback.

Acked-by: Ivan Boule <ivan.boule@6wind.com>
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
This commit is contained in:
Thomas Monjalon 2012-05-31 19:00:31 +02:00
parent ba9fe01bea
commit 7105562fb8
1 changed files with 42 additions and 5 deletions
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47
lib/librte_eal/linuxapp/eal/eal_hpet.c
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@ -129,14 +129,51 @@ hpet_msb_inc(__attribute__((unused)) void *arg)
}
}
static uint64_t
get_tsc_freq_from_cpuinfo(void)
{
char line[256];
FILE *stream;
double dmhz;
uint64_t freq = 0;
stream = fopen("/proc/cpuinfo", "r");
if (!stream) {
RTE_LOG(WARNING, EAL, "WARNING: Unable to open /proc/cpuinfo\n");
return 0;
}
while (fgets(line, sizeof line, stream)) {
if (sscanf(line, "cpu MHz\t: %lf", &dmhz) == 1) {
freq = (uint64_t)(dmhz * 1000000UL);
break;
}
}
fclose(stream);
return freq;
}
static uint64_t
get_tsc_freq_from_sleep(void)
{
uint64_t start = rte_rdtsc();
sleep(1);
return rte_rdtsc() - start;
}
static inline void
set_rdtsc_freq(void)
{
uint64_t start;
start = rte_rdtsc();
sleep(1);
eal_hpet_resolution_hz = rte_rdtsc() - start;
uint64_t freq;
freq = get_tsc_freq_from_cpuinfo();
if (!freq) {
RTE_LOG(WARNING, EAL, "WARNING: Cannot read CPU clock\n");
freq = get_tsc_freq_from_sleep();
}
RTE_LOG(INFO, EAL, "TSC clock @ %lu MHz\n",
(unsigned long) (freq / (1000000UL)));
eal_hpet_resolution_hz = freq;
eal_hpet_resolution_fs = (uint32_t)
((1.0 / eal_hpet_resolution_hz) / 1e-15);
}