From 9115e8cd2a0c6eaaa900c462721f12e1d45f326c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 3 Dec 2016 11:14:56 -0800 Subject: [PATCH] net: reorganize struct sock for better data locality Group fields used in TX path, and keep some cache lines mostly read to permit sharing among cpus. Gained two 4 bytes holes on 64bit arches. Added a place holder for tcp tsq_flags, next to sk_wmem_alloc to speed up tcp_wfree() in the following patch. I have not added ____cacheline_aligned_in_smp, this might be done later. I prefer doing this once inet and tcp/udp sockets reorg is also done. Tested with both TCP and UDP. UDP receiver performance under flood increased by ~20 % : Accessing sk_filter/sk_wq/sk_napi_id no longer stalls because sk_drops was moved away from a critical cache line, now mostly read and shared. /* --- cacheline 4 boundary (256 bytes) --- */ unsigned int sk_napi_id; /* 0x100 0x4 */ int sk_rcvbuf; /* 0x104 0x4 */ struct sk_filter * sk_filter; /* 0x108 0x8 */ union { struct socket_wq * sk_wq; /* 0x8 */ struct socket_wq * sk_wq_raw; /* 0x8 */ }; /* 0x110 0x8 */ struct xfrm_policy * sk_policy[2]; /* 0x118 0x10 */ struct dst_entry * sk_rx_dst; /* 0x128 0x8 */ struct dst_entry * sk_dst_cache; /* 0x130 0x8 */ atomic_t sk_omem_alloc; /* 0x138 0x4 */ int sk_sndbuf; /* 0x13c 0x4 */ /* --- cacheline 5 boundary (320 bytes) --- */ int sk_wmem_queued; /* 0x140 0x4 */ atomic_t sk_wmem_alloc; /* 0x144 0x4 */ long unsigned int sk_tsq_flags; /* 0x148 0x8 */ struct sk_buff * sk_send_head; /* 0x150 0x8 */ struct sk_buff_head sk_write_queue; /* 0x158 0x18 */ __s32 sk_peek_off; /* 0x170 0x4 */ int sk_write_pending; /* 0x174 0x4 */ long int sk_sndtimeo; /* 0x178 0x8 */ Signed-off-by: Eric Dumazet Tested-by: Paolo Abeni Signed-off-by: David S. Miller --- include/net/sock.h | 51 ++++++++++++++++++++++++---------------------- 1 file changed, 27 insertions(+), 24 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 69afda6bea15..6dfe3aa22b97 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -343,6 +343,9 @@ struct sock { #define sk_rxhash __sk_common.skc_rxhash socket_lock_t sk_lock; + atomic_t sk_drops; + int sk_rcvlowat; + struct sk_buff_head sk_error_queue; struct sk_buff_head sk_receive_queue; /* * The backlog queue is special, it is always used with @@ -359,14 +362,13 @@ struct sock { struct sk_buff *tail; } sk_backlog; #define sk_rmem_alloc sk_backlog.rmem_alloc - int sk_forward_alloc; - __u32 sk_txhash; + int sk_forward_alloc; #ifdef CONFIG_NET_RX_BUSY_POLL - unsigned int sk_napi_id; unsigned int sk_ll_usec; + /* ===== mostly read cache line ===== */ + unsigned int sk_napi_id; #endif - atomic_t sk_drops; int sk_rcvbuf; struct sk_filter __rcu *sk_filter; @@ -379,11 +381,30 @@ struct sock { #endif struct dst_entry *sk_rx_dst; struct dst_entry __rcu *sk_dst_cache; - /* Note: 32bit hole on 64bit arches */ - atomic_t sk_wmem_alloc; atomic_t sk_omem_alloc; int sk_sndbuf; + + /* ===== cache line for TX ===== */ + int sk_wmem_queued; + atomic_t sk_wmem_alloc; + unsigned long sk_tsq_flags; + struct sk_buff *sk_send_head; struct sk_buff_head sk_write_queue; + __s32 sk_peek_off; + int sk_write_pending; + long sk_sndtimeo; + struct timer_list sk_timer; + __u32 sk_priority; + __u32 sk_mark; + u32 sk_pacing_rate; /* bytes per second */ + u32 sk_max_pacing_rate; + struct page_frag sk_frag; + netdev_features_t sk_route_caps; + netdev_features_t sk_route_nocaps; + int sk_gso_type; + unsigned int sk_gso_max_size; + gfp_t sk_allocation; + __u32 sk_txhash; /* * Because of non atomicity rules, all @@ -414,42 +435,24 @@ struct sock { #define SK_PROTOCOL_MAX U8_MAX kmemcheck_bitfield_end(flags); - int sk_wmem_queued; - gfp_t sk_allocation; - u32 sk_pacing_rate; /* bytes per second */ - u32 sk_max_pacing_rate; - netdev_features_t sk_route_caps; - netdev_features_t sk_route_nocaps; - int sk_gso_type; - unsigned int sk_gso_max_size; u16 sk_gso_max_segs; - int sk_rcvlowat; unsigned long sk_lingertime; - struct sk_buff_head sk_error_queue; struct proto *sk_prot_creator; rwlock_t sk_callback_lock; int sk_err, sk_err_soft; u32 sk_ack_backlog; u32 sk_max_ack_backlog; - __u32 sk_priority; - __u32 sk_mark; kuid_t sk_uid; struct pid *sk_peer_pid; const struct cred *sk_peer_cred; long sk_rcvtimeo; - long sk_sndtimeo; - struct timer_list sk_timer; ktime_t sk_stamp; u16 sk_tsflags; u8 sk_shutdown; u32 sk_tskey; struct socket *sk_socket; void *sk_user_data; - struct page_frag sk_frag; - struct sk_buff *sk_send_head; - __s32 sk_peek_off; - int sk_write_pending; #ifdef CONFIG_SECURITY void *sk_security; #endif -- 2.20.1