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UDP busy polling is restricted to connected UDP sockets. This is because sk_busy_loop() only takes care of one NAPI context. There are cases where it could be extended. 1) Some hosts receive traffic on a single NIC, with one RX queue. 2) Some applications use SO_REUSEPORT and associated BPF filter to split the incoming traffic on one UDP socket per RX queue/thread/cpu 3) Some UDP sockets are used to send/receive traffic for one flow, but they do not bother with connect() This patch records the napi_id of first received skb, giving more reach to busy polling. Tested: lpaa23:~# echo 70 >/proc/sys/net/core/busy_read lpaa24:~# echo 70 >/proc/sys/net/core/busy_read lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5; done Before patch : 27867 28870 37324 41060 41215 36764 36838 44455 41282 43843 After patch : 73920 73213 70147 74845 71697 68315 68028 75219 70082 73707 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/*
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* net busy poll support
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* Copyright(c) 2013 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Author: Eliezer Tamir
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*
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* Contact Information:
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* e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
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*/
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#ifndef _LINUX_NET_BUSY_POLL_H
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#define _LINUX_NET_BUSY_POLL_H
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#include <linux/netdevice.h>
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#include <net/ip.h>
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#ifdef CONFIG_NET_RX_BUSY_POLL
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struct napi_struct;
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extern unsigned int sysctl_net_busy_read __read_mostly;
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extern unsigned int sysctl_net_busy_poll __read_mostly;
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/* return values from ndo_ll_poll */
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#define LL_FLUSH_FAILED -1
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#define LL_FLUSH_BUSY -2
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static inline bool net_busy_loop_on(void)
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{
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return sysctl_net_busy_poll;
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}
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static inline u64 busy_loop_us_clock(void)
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{
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return local_clock() >> 10;
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}
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static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
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{
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return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
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}
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/* in poll/select we use the global sysctl_net_ll_poll value */
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static inline unsigned long busy_loop_end_time(void)
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{
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return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
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}
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static inline bool sk_can_busy_loop(const struct sock *sk)
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{
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return sk->sk_ll_usec && sk->sk_napi_id && !signal_pending(current);
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}
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static inline bool busy_loop_timeout(unsigned long end_time)
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{
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unsigned long now = busy_loop_us_clock();
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return time_after(now, end_time);
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}
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bool sk_busy_loop(struct sock *sk, int nonblock);
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/* used in the NIC receive handler to mark the skb */
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static inline void skb_mark_napi_id(struct sk_buff *skb,
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struct napi_struct *napi)
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{
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skb->napi_id = napi->napi_id;
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}
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#else /* CONFIG_NET_RX_BUSY_POLL */
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static inline unsigned long net_busy_loop_on(void)
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{
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return 0;
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}
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static inline unsigned long busy_loop_end_time(void)
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{
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return 0;
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}
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static inline bool sk_can_busy_loop(struct sock *sk)
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{
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return false;
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}
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static inline void skb_mark_napi_id(struct sk_buff *skb,
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struct napi_struct *napi)
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{
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}
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static inline bool busy_loop_timeout(unsigned long end_time)
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{
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return true;
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}
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static inline bool sk_busy_loop(struct sock *sk, int nonblock)
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{
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return false;
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}
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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/* used in the protocol hanlder to propagate the napi_id to the socket */
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static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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sk->sk_napi_id = skb->napi_id;
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#endif
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}
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/* variant used for unconnected sockets */
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static inline void sk_mark_napi_id_once(struct sock *sk,
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const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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if (!sk->sk_napi_id)
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sk->sk_napi_id = skb->napi_id;
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#endif
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}
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#endif /* _LINUX_NET_BUSY_POLL_H */
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