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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	 Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
	 Eric Dumazet <edumazet@google.com>
Subject: [PATCH net-next 8/8] net: rps: move received_rps field to a better location
Date: Thu, 28 Mar 2024 17:03:09 +0000	[thread overview]
Message-ID: <20240328170309.2172584-9-edumazet@google.com> (raw)
In-Reply-To: <20240328170309.2172584-1-edumazet@google.com>

Commit 14d898f3c1b3 ("dev: Move received_rps counter next
to RPS members in softnet data") was unfortunate:

received_rps is dirtied by a cpu and never read by other
cpus in fast path.

Its presence in the hot RPS cache line (shared by many cpus)
is hurting RPS/RFS performance.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/netdevice.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 14f19cc2616452d7e6afbbaa52f8ad3e61a419e9..274d8db48b4858c70b43ea4628544e924ba6a263 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3203,6 +3203,7 @@ struct softnet_data {
 	struct softnet_data	*rps_ipi_list;
 #endif
 
+	unsigned int		received_rps;
 	bool			in_net_rx_action;
 	bool			in_napi_threaded_poll;
 
@@ -3235,7 +3236,6 @@ struct softnet_data {
 	unsigned int		cpu;
 	unsigned int		input_queue_tail;
 #endif
-	unsigned int		received_rps;
 	struct sk_buff_head	input_pkt_queue;
 	struct napi_struct	backlog;
 
-- 
2.44.0.478.gd926399ef9-goog


  parent reply	other threads:[~2024-03-28 17:03 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-28 17:03 [PATCH net-next 0/8] net: rps: misc changes Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 1/8] net: move kick_defer_list_purge() to net/core/dev.h Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 2/8] net: move dev_xmit_recursion() helpers " Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 3/8] net: enqueue_to_backlog() change vs not running device Eric Dumazet
2024-03-29  3:21   ` Jason Xing
2024-03-29  6:31     ` Eric Dumazet
2024-03-29  8:44       ` Jason Xing
2024-03-28 17:03 ` [PATCH net-next 4/8] net: make softnet_data.dropped an atomic_t Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 5/8] net: enqueue_to_backlog() cleanup Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 6/8] net: rps: change input_queue_tail_incr_save() Eric Dumazet
2024-03-29 12:07   ` kernel test robot
2024-03-29 12:29   ` kernel test robot
2024-03-28 17:03 ` [PATCH net-next 7/8] net: rps: add rps_input_queue_head_add() helper Eric Dumazet
2024-03-28 17:03 ` Eric Dumazet [this message]
2024-03-29  5:45 ` [PATCH net-next 0/8] net: rps: misc changes Jakub Kicinski
2024-03-29  6:44   ` Eric Dumazet

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