From 534643aac6c556ee5f9e83a5ef248979913941ad Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Wed, 26 Sep 2018 21:12:40 +0000
Subject: [PATCH] Performance tweak for Windows. See #1327

---
 libnetutil/netutil.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libnetutil/netutil.cc b/libnetutil/netutil.cc
index c7dfa5be8..31de2aff4 100644
--- a/libnetutil/netutil.cc
+++ b/libnetutil/netutil.cc
@@ -4153,7 +4153,11 @@ pcap_t *my_pcap_open_live(const char *device, int snaplen, int promisc, int to_m
   /* This is unnecessary with Npcap since libpcap calls PacketSetMinToCopy(0)
    * based on immediate mode. Have not determined if it is needed for WinPcap
    * or not, but it's not hurting anything. */
-  pcap_setmintocopy(pt, 1);
+  pcap_setmintocopy(pt, 0);
+  /* Npcap sets kernel buffer size to 1MB, but user buffer size to 256KB.
+   * Memory is pretty cheap these days, so lets match the kernel buffer size
+   * for better performance. */
+  pcap_setuserbuffer(pt, 1000000);
 #endif
 
   return pt;