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authorIvan Boule <ivan.boule@6wind.com>2012-05-31 18:41:57 +0200
committerThomas Monjalon <thomas.monjalon@6wind.com>2013-09-17 14:16:11 +0200
commit947b971aea95c9f508607883bd6849860316002e (patch)
treed432ad6f00cf57b7a3e5e20fd648df91dbd005f1
parent3f009de88d0d083534cb72bd77cd64458a340aca (diff)
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timer: check TSC reliability
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>
-rw-r--r--lib/librte_eal/linuxapp/eal/eal_timer.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/lib/librte_eal/linuxapp/eal/eal_timer.c b/lib/librte_eal/linuxapp/eal/eal_timer.c
index d046f59..67e45d6 100644
--- a/lib/librte_eal/linuxapp/eal/eal_timer.c
+++ b/lib/librte_eal/linuxapp/eal/eal_timer.c
@@ -2,6 +2,7 @@
* BSD LICENSE
*
* Copyright(c) 2010-2013 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
@@ -243,6 +244,41 @@ 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)
{
@@ -305,5 +341,6 @@ rte_eal_timer_init(void)
eal_timer_source = EAL_TIMER_TSC;
set_tsc_freq();
+ check_tsc_flags();
return 0;
}