Date: Thu, 27 May 2021 10:57:03 GMT From: Lutz Donnerhacke <donner@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 7fd88ba72eb3 - stable/13 - netgraph/ng_bridge: Avoid cache thrashing Message-ID: <202105271057.14RAv34W000108@gitrepo.freebsd.org>
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The branch stable/13 has been updated by donner: URL: https://cgit.FreeBSD.org/src/commit/?id=7fd88ba72eb353c9dd43063f5faea019ad5b0ea9 commit 7fd88ba72eb353c9dd43063f5faea019ad5b0ea9 Author: Lutz Donnerhacke <donner@FreeBSD.org> AuthorDate: 2021-02-11 22:59:11 +0000 Commit: Lutz Donnerhacke <donner@FreeBSD.org> CommitDate: 2021-05-27 10:55:52 +0000 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)) {
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