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kernel: add kernel_get_cpu_frequency()

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This commit is contained in:
Steffen Vogel 2018-08-13 14:40:36 +02:00
parent c2679fa1a4
commit 21b9ae1675
2 changed files with 63 additions and 0 deletions
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3
include/villas/kernel/kernel.h
View file

@ -90,6 +90,9 @@ int kernel_get_page_size();
/** Get the size of a huge page in bytes. */
int kernel_get_hugepage_size();
/** Get CPU base frequency */
int kernel_get_cpu_frequency(uint64_t *freq);
/** Set SMP affinity of IRQ */
int kernel_irq_setaffinity(unsigned irq, uintmax_t aff , uintmax_t *old );

60
lib/kernel/kernel.c
View file

@ -281,4 +281,64 @@ int kernel_irq_setaffinity(unsigned irq, uintmax_t aff, uintmax_t *old)
return ret;
}
int kernel_get_cpu_frequency(uint64_t *freq)
{
char *line = NULL, *sep, *end;
size_t len = 0;
double dfreq;
int ret;
FILE *f;
/* Try to get CPU frequency from cpufreq module */
f = fopen(SYSFS_PATH "/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", "r");
if (!f)
goto cpuinfo;
ret = fscanf(f, "%" PRIu64, freq);
fclose(f);
if (ret != 1)
return -1;
/* cpufreq reports kHz */
*freq = *freq * 1000;
return 0;
cpuinfo:
/* Try to read CPU frequency from /proc/cpuinfo */
f = fopen(PROCFS_PATH "/cpuinfo", "r");
if (!f)
return -1; /* We give up here */
ret = -1;
while (getline(&line, &len, f) >= 0) {
if (strstr(line, "cpu MHz") == line) {
ret = 0;
break;
}
}
if (ret)
goto out;
sep = strchr(line, ':');
if (!sep) {
ret = -1;
goto out;
}
dfreq = strtod(sep+1, &end);
if (end == sep+1) {
ret = -1;
goto out;
}
/* Frequency is given in MHz */
*freq = dfreq * 1e6;
out: fclose(f);
free(line);
return ret;
}
#endif /* __linux__ */