From 7fd88ba72eb353c9dd43063f5faea019ad5b0ea9 Mon Sep 17 00:00:00 2001 From: Lutz Donnerhacke Date: Thu, 11 Feb 2021 23:59:11 +0100 Subject: netgraph/ng_bridge: Avoid cache thrashing Hint the compiler, that this update is needed at most once per second. Only in this case the memory line needs to be written. This will reduce the amount of cache trashing during forward of most frames. Suggested by: zec Approved by: zec Differential Revision: https://reviews.freebsd.org/D28601 (cherry picked from commit 4dfe70fdbda05453e824bc9edfc0d09eab7b2929) --- sys/netgraph/ng_bridge.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sys/netgraph/ng_bridge.c b/sys/netgraph/ng_bridge.c index 0bed50fc240b..baedeb911e6d 100644 --- a/sys/netgraph/ng_bridge.c +++ b/sys/netgraph/ng_bridge.c @@ -863,7 +863,8 @@ ng_bridge_rcvdata(hook_p hook, item_p item) * This is safe without locking, because it's * the only operation during shared access. */ - host->staleness = 0; + if (__predict_false(host->staleness > 0)) + host->staleness = 0; if ((host == NULL && ctx.incoming->learnMac) || (host != NULL && host->link != ctx.incoming)) { -- cgit v1.2.3