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timer: check TSC reliability

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Read flags from /proc/cpuinfo and warn if constant_tsc or nonstop_tsc is
not found.

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Acked-by: Ivan Boule <ivan.boule@6wind.com>
This commit is contained in:
Ivan Boule 2012-05-31 16:41:57 +02:00 committed by David Marchand
parent 73a2bc5dba
commit fb022b85ba
1 changed files with 37 additions and 0 deletions
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37
lib/librte_eal/linuxapp/eal/eal_timer.c
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@ -2,6 +2,7 @@
* BSD LICENSE
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
* Copyright(c) 2012-2013 6WIND S.A.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -242,6 +243,41 @@ rte_eal_hpet_init(int make_default)
}
#endif
static void
check_tsc_flags(void)
{
char line[512];
FILE *stream;
stream = fopen("/proc/cpuinfo", "r");
if (!stream) {
RTE_LOG(WARNING, EAL, "WARNING: Unable to open /proc/cpuinfo\n");
return;
}
while (fgets(line, sizeof line, stream)) {
char *constant_tsc;
char *nonstop_tsc;
if (strncmp(line, "flags", 5) != 0)
continue;
constant_tsc = strstr(line, "constant_tsc");
nonstop_tsc = strstr(line, "nonstop_tsc");
if (!constant_tsc || !nonstop_tsc)
RTE_LOG(WARNING, EAL,
"WARNING: cpu flags "
"constant_tsc=%s "
"nonstop_tsc=%s "
"-> using unreliable clock cycles !\n",
constant_tsc ? "yes":"no",
nonstop_tsc ? "yes":"no");
break;
}
fclose(stream);
}
static int
set_tsc_freq_from_clock(void)
{
@ -304,5 +340,6 @@ rte_eal_timer_init(void)
eal_timer_source = EAL_TIMER_TSC;
set_tsc_freq();
check_tsc_flags();
return 0;
}