packet drop issue resolution

core/modules/measure.cc

@@ -110,9 +110,6 @@ void Measure::ProcessBatch(Context *ctx, bess::PacketBatch *batch) {
   uint64_t now_ns = tsc_to_ns(rdtsc());
   size_t offset = offset_;
 
-  mcslock_node_t mynode;
-  mcs_lock(&lock_, &mynode);
-
   pkt_cnt_ += batch->cnt();
 
   int cnt = batch->cnt();
@@ -132,21 +129,20 @@ void Measure::ProcessBatch(Context *ctx, bess::PacketBatch *batch) {
 
       bytes_cnt_ += batch->pkts()[i]->total_len();
 
-      rtt_hist_.Insert(diff);
+      rtt_hist_.AtomicInsert(diff);
       if (rand_.GetRealNonzero() <= jitter_sample_prob_) {
         if (unlikely(!last_rtt_ns_)) {
           last_rtt_ns_ = diff;
           continue;
         }
-        uint64_t jitter = absdiff(diff, last_rtt_ns_);
-        jitter_hist_.Insert(jitter);
+        int64_t jitter = diff - last_rtt_ns_;
+        jitter = jitter * ((jitter>0) - (jitter<0));
+        jitter_hist_.AtomicInsert(jitter);
         last_rtt_ns_ = diff;
       }
     }
   }
 
-  mcs_unlock(&lock_, &mynode);
-
   RunNextModule(ctx, batch);
 }
 

core/modules/measure.h

@@ -38,7 +38,7 @@
 #include "../utils/histogram.h"
 #include "../utils/mcslock.h"
 #include "../utils/random.h"
-
+#include <atomic>
 class Measure final : public Module {
  public:
   Measure(uint64_t ns_per_bucket = 1, uint64_t max_ns = 0)
@@ -69,22 +69,18 @@ class Measure final : public Module {
   static const uint64_t kDefaultNsPerBucket = 100;
   static const uint64_t kDefaultMaxNs = 100'000'000;  // 100 ms
   static constexpr double kDefaultIpDvSampleProb = 0.05;
-
   void Clear();
-
   Histogram<uint64_t> rtt_hist_;
   Histogram<uint64_t> jitter_hist_;
 
   Random rand_;
   double jitter_sample_prob_;
-  uint64_t last_rtt_ns_;
-
+  std::atomic<std::uint64_t> last_rtt_ns_;
   size_t offset_;  // in bytes
   int attr_id_;
 
-  uint64_t pkt_cnt_;
-  uint64_t bytes_cnt_;
-
+  std::atomic<std::uint64_t> pkt_cnt_;
+  std::atomic<std::uint64_t> bytes_cnt_;
   mcslock lock_;
 };