Hi

Patch applied - but no big change - from 0.7Mpps per vlan to 1.2Mpps per vlan

previously(without patch) 100% cpu load:

  bwm-ng v0.6.1 (probing every 0.500s), press 'h' for help
  input: /proc/net/dev type: rate
  |         iface                   Rx Tx                Total
============================================================================== vlan1002: 0.00 P/s 1.99 P/s 1.99 P/s
         vlan1001:            0.00 P/s        717227.12 P/s 717227.12 P/s
       enp175s0f0:      2713679.25 P/s             0.00 P/s 2713679.25 P/s
         vlan1000:            0.00 P/s        716145.44 P/s 716145.44 P/s
------------------------------------------------------------------------------
            total:      2713679.25 P/s       1433374.50 P/s 4147054.00 P/s


With patch (100% cpu load a little better pps performance)

 bwm-ng v0.6.1 (probing every 1.000s), press 'h' for help
  input: /proc/net/dev type: rate
  |         iface                   Rx Tx                Total
==============================================================================
vlan1002: 0.00 P/s 1.00 P/s 1.00 P/s
         vlan1001:            0.00 P/s       1202161.50 P/s 1202161.50 P/s
       enp175s0f0:      3699864.50 P/s             0.00 P/s 3699864.50 P/s
         vlan1000:            0.00 P/s       1196870.38 P/s 1196870.38 P/s
------------------------------------------------------------------------------
            total:      3699864.50 P/s       2399033.00 P/s 6098897.50 P/s


perf top attached below:

     1.90%     0.00%  ksoftirqd/39    [kernel.vmlinux] [k] run_ksoftirqd
            |
             --1.90%--run_ksoftirqd
                       |
                        --1.90%--__softirqentry_text_start
                                  |
                                   --1.90%--net_rx_action
                                             |
--1.90%--mlx5e_napi_poll
                                                        |
--1.89%--mlx5e_poll_rx_cq
|
--1.88%--mlx5e_handle_rx_cqe
|
--1.85%--napi_gro_receive
|
--1.85%--netif_receive_skb_internal
|
--1.85%--__netif_receive_skb
|
--1.85%--__netif_receive_skb_core
|
--1.85%--ip_rcv
|
--1.85%--ip_rcv_finish
|
--1.83%--ip_forward
|
--1.82%--ip_forward_finish
|
--1.82%--ip_output
|
--1.82%--ip_finish_output
|
--1.82%--ip_finish_output2
|
--1.79%--neigh_resolve_output
|
--1.77%--neigh_event_send
|
--1.77%--__neigh_event_send
|
--1.74%--_raw_write_lock_bh
|
--1.74%--queued_write_lock
queued_write_lock_slowpath
|
--1.70%--queued_spin_lock_slowpath


1.90% 0.00% ksoftirqd/34 [kernel.vmlinux] [k] __softirqentry_text_start
            |
            ---__softirqentry_text_start
               |
                --1.90%--net_rx_action
                          |
                           --1.90%--mlx5e_napi_poll
                                     |
                                      --1.89%--mlx5e_poll_rx_cq
                                                |
--1.88%--mlx5e_handle_rx_cqe
                                                           |
--1.86%--napi_gro_receive
                                                                      |
--1.85%--netif_receive_skb_internal
|
--1.85%--__netif_receive_skb
|
--1.85%--__netif_receive_skb_core
|
--1.85%--ip_rcv
|
--1.85%--ip_rcv_finish
|
--1.83%--ip_forward
|
--1.82%--ip_forward_finish
|
--1.82%--ip_output
|
--1.82%--ip_finish_output
|
--1.82%--ip_finish_output2
|
--1.79%--neigh_resolve_output
|
--1.77%--neigh_event_send
|
--1.77%--__neigh_event_send
|
--1.74%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.71%--queued_spin_lock_slowpath

1.85% 0.00% ksoftirqd/38 [kernel.vmlinux] [k] ip_rcv_finish
            |
             --1.85%--ip_rcv_finish
                       |
                        --1.83%--ip_forward
                                  |
                                   --1.82%--ip_forward_finish
                                             |
                                              --1.82%--ip_output
                                                        |
--1.82%--ip_finish_output
|
--1.82%--ip_finish_output2
|
--1.79%--neigh_resolve_output
|
--1.77%--neigh_event_send
|
--1.77%--__neigh_event_send
|
--1.74%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.71%--queued_spin_lock_slowpath

     1.85%     0.00%  ksoftirqd/22    [kernel.vmlinux] [k] ip_rcv
            |
             --1.85%--ip_rcv
                       |
                        --1.85%--ip_rcv_finish
                                  |
                                   --1.83%--ip_forward
                                             |
--1.82%--ip_forward_finish
                                                        |
--1.82%--ip_output
|
--1.82%--ip_finish_output
|
--1.82%--ip_finish_output2
|
--1.79%--neigh_resolve_output
|
--1.77%--neigh_event_send
|
--1.77%--__neigh_event_send
|
--1.73%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.70%--queued_spin_lock_slowpath

1.83% 0.00% ksoftirqd/9 [kernel.vmlinux] [k] ip_forward
            |
             --1.83%--ip_forward
                       |
                        --1.82%--ip_forward_finish
                                  |
                                   --1.82%--ip_output
                                             |
--1.82%--ip_finish_output
                                                        |
--1.82%--ip_finish_output2
                                                                   |
--1.79%--neigh_resolve_output
|
--1.77%--neigh_event_send
|
--1.77%--__neigh_event_send
|
--1.74%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.70%--queued_spin_lock_slowpath


1.82% 0.00% ksoftirqd/35 [kernel.vmlinux] [k] ip_output
            |
             --1.82%--ip_output
                       |
                        --1.82%--ip_finish_output
                                  |
                                   --1.82%--ip_finish_output2
                                             |
--1.79%--neigh_resolve_output
                                                        |
--1.77%--neigh_event_send
                                                                   |
--1.77%--__neigh_event_send
|
--1.74%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.71%--queued_spin_lock_slowpath

1.82% 0.00% ksoftirqd/38 [kernel.vmlinux] [k] ip_finish_output
            |
             --1.82%--ip_finish_output
                       |
                        --1.82%--ip_finish_output2
                                  |
                                   --1.79%--neigh_resolve_output
                                             |
--1.77%--neigh_event_send
                                                        |
--1.77%--__neigh_event_send
                                                                   |
--1.74%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.71%--queued_spin_lock_slowpath

1.82% 0.00% ksoftirqd/37 [kernel.vmlinux] [k] ip_forward_finish
            |
             --1.82%--ip_forward_finish
                       ip_output
                       |
                        --1.82%--ip_finish_output
                                  |
                                   --1.82%--ip_finish_output2
                                             |
--1.79%--neigh_resolve_output
                                                        |
--1.76%--neigh_event_send
__neigh_event_send
                                                                   |
--1.73%--_raw_write_lock_bh
queued_write_lock
queued_write_lock_slowpath
|
--1.70%--queued_spin_lock_slowpath


W dniu 2017-08-16 o 09:42, Julian Anastasov pisze:
        Hello,

On Tue, 15 Aug 2017, Eric Dumazet wrote:

It must be possible to add a fast path without locks.

(say if jiffies has not changed before last state change)
        New day - new idea. Something like this? But it
has bug: without checking neigh->dead under lock we don't
have the right to access neigh->parms, it can be destroyed
immediately by neigh_release->neigh_destroy->neigh_parms_put->
neigh_parms_destroy->kfree. Not sure, may be kfree_rcu can help
for this...

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 9816df2..f52763c 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -428,10 +428,10 @@ static inline int neigh_event_send(struct neighbour 
*neigh, struct sk_buff *skb)
  {
        unsigned long now = jiffies;
        
-       if (neigh->used != now)
-               neigh->used = now;
        if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
                return __neigh_event_send(neigh, skb);
+       if (neigh->used != now)
+               neigh->used = now;
        return 0;
  }
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 16a1a4c..52a8718 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -991,8 +991,18 @@ static void neigh_timer_handler(unsigned long arg)
int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
  {
-       int rc;
        bool immediate_probe = false;
+       unsigned long now = jiffies;
+       int rc;
+
+       if (neigh->used != now) {
+               neigh->used = now;
+       } else if (neigh->nud_state == NUD_INCOMPLETE &&
+                  (!skb || neigh->arp_queue_len_bytes + skb->truesize >
+                   NEIGH_VAR(neigh->parms, QUEUE_LEN_BYTES))) {
+               kfree_skb(skb);
+               return 1;
+       }
write_lock_bh(&neigh->lock); @@ -1005,7 +1015,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
        if (!(neigh->nud_state & (NUD_STALE | NUD_INCOMPLETE))) {
                if (NEIGH_VAR(neigh->parms, MCAST_PROBES) +
                    NEIGH_VAR(neigh->parms, APP_PROBES)) {
-                       unsigned long next, now = jiffies;
+                       unsigned long next;
atomic_set(&neigh->probes,
                                   NEIGH_VAR(neigh->parms, UCAST_PROBES));

Regards

--
Julian Anastasov <j...@ssi.bg>


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