timer: remove useless check on x86 TSC reliability

This code was added 7+ years ago in
commit fb022b85bae4 ("timer: check TSC reliability")
presumably when variant TSCs were still somewhat common.

But this code doesn't do anything except print a warning,
and the warning doesn't give any kind of advice to the user,
so let's just remove it.

While the warning has no functional meaning, the /proc/cpuinfo
parsing consumes a non-trivial amount of time which is especially
noticeable in secondary processes.
On my test system, it consumes 21ms out of the 66ms total execution
time for rte_eal_init() in a secondary process.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

diff --git a/lib/librte_eal/linux/eal/eal_timer.c b/lib/librte_eal/linux/eal/eal_timer.c
index 76ec170..a904a82 100644 (file)
--- a/lib/librte_eal/linux/eal/eal_timer.c
+++ b/lib/librte_eal/linux/eal/eal_timer.c
@@ -192,41 +192,6 @@ 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);
-}
-
 uint64_t
 get_tsc_freq(void)
 {
@@ -263,6 +228,5 @@ rte_eal_timer_init(void)
        eal_timer_source = EAL_TIMER_TSC;
 
        set_tsc_freq();
-       check_tsc_flags();
        return 0;
 }