only store the current time on address table entries if it changes.

this avoids unecessary writes to memory. it helps a little bit with
a single nettq, but we get a lot more of a boost in pps when running
concurrently.

thanks to hrvoje for testing.

diff --git a/sys/net/if_etherbridge.c b/sys/net/if_etherbridge.c
index 451781a..d348802 100644 (file)
--- a/sys/net/if_etherbridge.c
+++ b/sys/net/if_etherbridge.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_etherbridge.c,v 1.4 2021/02/26 01:28:51 dlg Exp $ */
+/*     $OpenBSD: if_etherbridge.c,v 1.5 2021/02/26 08:31:23 dlg Exp $ */
 
 /*
  * Copyright (c) 2018, 2021 David Gwynne <dlg@openbsd.org>
@@ -299,10 +299,12 @@ etherbridge_map(struct etherbridge *eb, void *port, uint64_t eba)
        unsigned int num;
        void *nport;
        int new = 0;
+       time_t now;
 
        if (ETH64_IS_MULTICAST(eba) || ETH64_IS_ANYADDR(eba))
                return;
 
+       now = getuptime();
        ebl = etherbridge_list(eb, eba);
 
        smr_read_enter();
@@ -310,7 +312,8 @@ etherbridge_map(struct etherbridge *eb, void *port, uint64_t eba)
        if (oebe == NULL)
                new = 1;
        else {
-               oebe->ebe_age = getuptime();
+               if (oebe->ebe_age != now)
+                       oebe->ebe_age = now;
 
                /* does this entry need to be replaced? */
                if (oebe->ebe_type == EBE_DYNAMIC &&
@@ -345,7 +348,7 @@ etherbridge_map(struct etherbridge *eb, void *port, uint64_t eba)
        nebe->ebe_addr = eba;
        nebe->ebe_port = nport;
        nebe->ebe_type = EBE_DYNAMIC;
-       nebe->ebe_age = getuptime();
+       nebe->ebe_age = now;
 
        mtx_enter(&eb->eb_lock);
        num = eb->eb_num + (oebe == NULL);