[dpdk-dev] [PATCH] timer: remove check_tsc_flags()
Jim Harris
james.r.harris at intel.com
Wed Aug 21 12:11:59 CEST 2019
This code was added 7+ years ago (commit fb022b85ba),
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 at intel.com>
---
lib/librte_eal/linux/eal/eal_timer.c | 36 ----------------------------------
1 file changed, 36 deletions(-)
diff --git a/lib/librte_eal/linux/eal/eal_timer.c b/lib/librte_eal/linux/eal/eal_timer.c
index 76ec17034..a904a8297 100644
--- 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;
}
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