On Wed, 2015-12-16 at 10:03 -0800, Haiyang Zhang wrote: > To avoid performance overhead when using skb_flow_dissect_flow_keys(), > we switch to the simple parsers to get the IP and port numbers. > > Performance comparison: throughput (Gbps): > Number of connections, before patch, after patch > 1 8.56 10.18 > 4 11.17 14.07 > 16 12.21 21.78 > 64 18.71 32.08 > 256 15.92 26.32 > 1024 8.41 15.49 > 3000 7.82 11.58 > > Signed-off-by: Haiyang Zhang <haiya...@microsoft.com> > Tested-by: Simon Xiao <six...@microsoft.com> > Reviewed-by: K. Y. Srinivasan <k...@microsoft.com> > --- > drivers/net/hyperv/netvsc_drv.c | 38 +++++++++++++++++++++++++++++--------- > 1 files changed, 29 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c > index 1c8db9a..e28951f 100644 > --- a/drivers/net/hyperv/netvsc_drv.c > +++ b/drivers/net/hyperv/netvsc_drv.c > @@ -237,20 +237,40 @@ static u32 comp_hash(u8 *key, int klen, void *data, int > dlen) > > static bool netvsc_set_hash(u32 *hash, struct sk_buff *skb) > { > - struct flow_keys flow; > + struct iphdr *iphdr; > + struct ipv6hdr *ipv6hdr; > + __be32 dbuf[9]; > int data_len; > > - if (!skb_flow_dissect_flow_keys(skb, &flow, 0) || > - !(flow.basic.n_proto == htons(ETH_P_IP) || > - flow.basic.n_proto == htons(ETH_P_IPV6))) > + if (eth_hdr(skb)->h_proto != htons(ETH_P_IP) && > + eth_hdr(skb)->h_proto != htons(ETH_P_IPV6)) > return false; > > - if (flow.basic.ip_proto == IPPROTO_TCP) > - data_len = 12; > - else > - data_len = 8; > + iphdr = ip_hdr(skb); > + ipv6hdr = ipv6_hdr(skb); > + > + if (iphdr->version == 4) { > + dbuf[0] = iphdr->saddr; > + dbuf[1] = iphdr->daddr; > + if (iphdr->protocol == IPPROTO_TCP) { > + dbuf[2] = *(__be32 *)&tcp_hdr(skb)->source; > + data_len = 12; > + } else { > + data_len = 8; > + } > + } else if (ipv6hdr->version == 6) { > + memcpy(dbuf, &ipv6hdr->saddr, 32); > + if (ipv6hdr->nexthdr == IPPROTO_TCP) { > + dbuf[8] = *(__be32 *)&tcp_hdr(skb)->source; > + data_len = 36; > + } else { > + data_len = 32; > + } > + } else { > + return false; > + } > > - *hash = comp_hash(netvsc_hash_key, HASH_KEYLEN, &flow, data_len); > + *hash = comp_hash(netvsc_hash_key, HASH_KEYLEN, dbuf, data_len); > > return true; > }
This looks very very wrong to me. How many times this is called per second, for the 'one flow' case ? Don't you use TSO in this driver ? What about encapsulation ? I suspect you have a quite different issue here. You simply could use skb_get_hash() since local TCP flows will provide a l4 skb->hash and you have no further flow dissection to do. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/