[dpdk-dev] [PATCH v4] timer: don't check tsc flags in secondary processes

[Jim Harris]

check_tsc_flags() parses /proc/cpuinfo and prints
warning messages if any cores don't have constant_tsc
and nonstop_tsc.  It has no functional meaning.
This consumes a noticeable amount of time in
secondary processes - on my test system, it consumes
21ms out of the 66ms total execution time for
rte_eal_init().

So let's just skip checking these flags in secondary
processes.  Since the primary process is already
parsing the entirety of /proc/cpuinfo, the warning
printed in the primary process should be sufficient.

Signed-off-by: Jim Harris <james.r.har...@intel.com>
---
 lib/librte_eal/linux/eal/eal_timer.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/librte_eal/linux/eal/eal_timer.c 
b/lib/librte_eal/linux/eal/eal_timer.c
index 76ec17034..ce447d43b 100644
--- a/lib/librte_eal/linux/eal/eal_timer.c
+++ b/lib/librte_eal/linux/eal/eal_timer.c
@@ -198,6 +198,15 @@ check_tsc_flags(void)
        char line[512];
        FILE *stream;
 
+       if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
+               /* This function just prints warnings if TSC is not constant
+                * and has no functional meaning.  It also checks *all* cores
+                * on the system, not just the ones configured for this process.
+                * So don't bother rechecking again in secondary processes.
+                */
+               return;
+       }
+
        stream = fopen("/proc/cpuinfo", "r");
        if (!stream) {
                RTE_LOG(WARNING, EAL, "WARNING: Unable to open 
/proc/cpuinfo\n");