dpdk-ring - prefetch dequeued packets before processing

Author: TheSableCZ

input/dpdk-ring.cpp

@@ -196,6 +196,7 @@ InputPlugin::Result DpdkRingReader::get(PacketBlock& packets)
     if (pkts_read_ == 0) {
         return Result::TIMEOUT;
     }
+    prefetchPackets();
     for (auto i = 0; i < pkts_read_; i++) {
         parse_packet(&opt,
             m_parser_stats,
@@ -256,4 +257,11 @@ void DpdkRingReader::getDynfieldInfo()
     }
 }
 
+void DpdkRingReader::prefetchPackets() {
+    for (auto i = 0; i < pkts_read_; i++) {
+        __builtin_prefetch(mbufs_[i], 0, 2);
+        __builtin_prefetch((uint8_t*)mbufs_[i] + 64, 0, 2);
+    }
+}
+
 } // namespace ipxp

input/dpdk-ring.h

@@ -152,6 +152,7 @@ class DpdkRingReader : public InputPlugin {
 
     telemetry::Content get_queue_telemetry();
     void getDynfieldInfo();
+    void prefetchPackets();
 
     std::vector<rte_mbuf *> mbufs_;
     std::uint16_t pkts_read_;