commit 57a1f8603b3f1eedec6e28f9d0ad861134f4ac0f
author Denton Gentry <dgentry@google.com> Sat Jan 09 14:28:32 2016 -0800
committer Denton Gentry <dgentry@google.com> Thu Mar 10 12:57:31 2016 -0800
tree 94f96fbc075d3e7c7f5d890e558908077cd2302a
parent 4a17883189ed3ed006f88561d56797d813972f98

netusage: log unipkts underflow details

We're still seeing underflows in the unipkts count,
where it reports a small negative number as a large
positive number. Log details to try to figure out
what is happening.

Change-Id: I94a8508192ed1a4a8a811aaa2486b9feb9d4cb3e

cmds/netusage.c

diff --git a/cmds/netusage.c b/cmds/netusage.c
index 8c0e1b5..dec2c20 100644
--- a/cmds/netusage.c
+++ b/cmds/netusage.c
@@ -174,6 +174,7 @@
   uint32_t tx_bytes, rx_bytes, tx_pkts, rx_pkts, rx_multipkts;
   uint32_t tx_bytes2, rx_bytes2, tx_pkts2, rx_pkts2, rx_multipkts2;
   uint32_t rx_unipkts;
+  static int max_underflow_log = 10;
 
   sendreq(s, interface);
   recvresp(s, &tx_bytes, &rx_bytes, &tx_pkts, &rx_pkts, &rx_multipkts);
@@ -207,6 +208,15 @@
   *rx_uni_pps = (rx_unipkts - old->rx_unipkts) / delta;
   *rx_multi_pps = (rx_multipkts - old->rx_multipkts) / delta;
 
+  if (*rx_uni_pps > (double)0x80000000) {
+    *rx_uni_pps = 0;
+    if (max_underflow_log > 0) {
+      printf("rx_unipkts underflow: pkts2 %u multipkts %u old_unipkts %u\n",
+          rx_pkts2, rx_multipkts, old->rx_unipkts);
+      max_underflow_log--;
+    }
+  }
+
   old->tx_bytes = tx_bytes;
   old->rx_bytes = rx_bytes;
   old->tx_pkts = tx_pkts;