RE: any change in socket systemcall or packet_mmap regarding multiqueue nic?

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mercredi 19 mai 2010 à 03:36 -0700, Jon Zhou a écrit :
> 
> -----Original Message-----
> From: Eric Dumazet [mailto:eric.dumazet@gmail.com] 
> Sent: Wednesday, May 19, 2010 12:25 PM
> To: Jon Zhou
> Cc: netdev@vger.kernel.org
> Subject: Re: any change in socket systemcall or packet_mmap regarding multiqueue nic?
> 
> Le mardi 18 mai 2010 à 19:55 -0700, Jon Zhou a écrit :
> > hi
> > the multiqueue networking can utilize multi-core to process packets from multiqueue nic,
> > but any change in related userspace application part, such as socket system call, packet_mmap? these userspace API can also utilize multicore to process packets from kernel?
> > otherwise they have to read data in serialization
> > 
> 
> Thats a bit general question. Works are in progress.
> 
> So far, you can use a new condition in filters to match a given queue
> index for incoming packets. A sniffer could setup N different sockets to
> receive data from N NIC queues.
> 
> jon->is it something like "ioctl(fd,SOL_SOCKET,queue_id...),could you tell the keyword?

keyword is BPF (used in libpcap) and SKF_AD_QUEUE instruction

Kernel part is ready :

commit d19742fb1c68e6db83b76e06dea5a374c99e104f
Author: Eric Dumazet <eric.dumazet@gmail.com>
Date:   Tue Oct 20 01:06:22 2009 -0700

    filter: Add SKF_AD_QUEUE instruction
    
    It can help being able to filter packets on their queue_mapping.
    
    If filter performance is not good, we could add a "numqueue" field
    in struct packet_type, so that netif_nit_deliver() and other
functions
    can directly ignore packets with not expected queue number.
    
    Lets experiment this simple filter extension first.
    
    Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 909193e..bb3b435 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -124,7 +124,8 @@ struct sock_fprog   /* Required for
SO_ATTACH_FILTER. */
 #define SKF_AD_NLATTR  12
 #define SKF_AD_NLATTR_NEST     16
 #define SKF_AD_MARK    20
-#define SKF_AD_MAX     24
+#define SKF_AD_QUEUE   24
+#define SKF_AD_MAX     28
 #define SKF_NET_OFF   (-0x100000)
 #define SKF_LL_OFF    (-0x200000)
 
diff --git a/net/core/filter.c b/net/core/filter.c
index e3987e1..08db7b9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -306,6 +306,9 @@ load_b:
                case SKF_AD_MARK:
                        A = skb->mark;
                        continue;
+               case SKF_AD_QUEUE:
+                       A = skb->queue_mapping;
+                       continue;
                case SKF_AD_NLATTR: {
                        struct nlattr *nla;