From: Jakub Kicinski Date: Wed, 18 Dec 2024 03:37:02 +0000 (-0800) Subject: Merge branch 'inetpeer-reduce-false-sharing-and-atomic-operations' X-Git-Tag: v6.14-rc1~162^2~199 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3a4130550998f23762184b0de4cc9163a3f2c49d;p=thirdparty%2Flinux.git Merge branch 'inetpeer-reduce-false-sharing-and-atomic-operations' Eric Dumazet says: ==================== inetpeer: reduce false sharing and atomic operations After commit 8c2bd38b95f7 ("icmp: change the order of rate limits"), there is a risk that a host receiving packets from an unique source targeting closed ports is using a common inet_peer structure from many cpus. All these cpus have to acquire/release a refcount and update the inet_peer timestamp (p->dtime) Switch to pure RCU to avoid changing the refcount, and update p->dtime only once per jiffy. Tested: DUT : 128 cores, 32 hw rx queues. receiving 8,400,000 UDP packets per second, targeting closed ports. Before the series: - napi poll can not keep up, NIC drops 1,200,000 packets per second. - We use 20 % of cpu cycles After this series: - All packets are received (no more hw drops) - We use 12 % of cpu cycles. v1: https://lore.kernel.org/20241213130212.1783302-1-edumazet@google.com ==================== Link: https://patch.msgid.link/20241215175629.1248773-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- 3a4130550998f23762184b0de4cc9163a3f2c49d