From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [Bugme-new] [Bug 11316] New: severe performance regression for iptables nat routing Date: Fri, 15 Aug 2008 14:54:34 -0700 (PDT) Message-ID: <20080815.145434.259306809.davem@davemloft.net> References: <20080815073343.GA20644@gondor.apana.org.au> <20080815081442.GA20971@gondor.apana.org.au> <20080815103235.GA31963@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: alex.williamson@hp.com, kaber@trash.net, akpm@linux-foundation.org, buytenh@marvell.com, netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org To: herbert@gondor.apana.org.au Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:54093 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751995AbYHOVyf (ORCPT ); Fri, 15 Aug 2008 17:54:35 -0400 In-Reply-To: <20080815103235.GA31963@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Fri, 15 Aug 2008 20:32:35 +1000 > loopback: Enable TSO > > This patch enables TSO since the loopback device is naturally > capable of handling packets of any size. This also means that > we won't enable GSO on lo which is good until GSO is fixed to > preserve netfilter state as netfilter treats loopback packets > in a special way. > > Signed-off-by: Herbert Xu Meanwhile I applied this and I took the liberty of applying the following right afterwards: loopback: Remove rest of LOOPBACK_TSO code. It hasn't been enabled for a long time and the generic GSO engine is better documentation of what is expected of a device implementing TSO. Signed-off-by: David S. Miller --- drivers/net/loopback.c | 62 ------------------------------------------------ 1 files changed, 0 insertions(+), 62 deletions(-) diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c index 46e87cc..489d53b 100644 --- a/drivers/net/loopback.c +++ b/drivers/net/loopback.c @@ -64,68 +64,6 @@ struct pcpu_lstats { unsigned long bytes; }; -/* KISS: just allocate small chunks and copy bits. - * - * So, in fact, this is documentation, explaining what we expect - * of largesending device modulo TCP checksum, which is ignored for loopback. - */ - -#ifdef LOOPBACK_TSO -static void emulate_large_send_offload(struct sk_buff *skb) -{ - struct iphdr *iph = ip_hdr(skb); - struct tcphdr *th = (struct tcphdr *)(skb_network_header(skb) + - (iph->ihl * 4)); - unsigned int doffset = (iph->ihl + th->doff) * 4; - unsigned int mtu = skb_shinfo(skb)->gso_size + doffset; - unsigned int offset = 0; - u32 seq = ntohl(th->seq); - u16 id = ntohs(iph->id); - - while (offset + doffset < skb->len) { - unsigned int frag_size = min(mtu, skb->len - offset) - doffset; - struct sk_buff *nskb = alloc_skb(mtu + 32, GFP_ATOMIC); - - if (!nskb) - break; - skb_reserve(nskb, 32); - skb_set_mac_header(nskb, -ETH_HLEN); - skb_reset_network_header(nskb); - iph = ip_hdr(nskb); - skb_copy_to_linear_data(nskb, skb_network_header(skb), - doffset); - if (skb_copy_bits(skb, - doffset + offset, - nskb->data + doffset, - frag_size)) - BUG(); - skb_put(nskb, doffset + frag_size); - nskb->ip_summed = CHECKSUM_UNNECESSARY; - nskb->dev = skb->dev; - nskb->priority = skb->priority; - nskb->protocol = skb->protocol; - nskb->dst = dst_clone(skb->dst); - memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); - nskb->pkt_type = skb->pkt_type; - - th = (struct tcphdr *)(skb_network_header(nskb) + iph->ihl * 4); - iph->tot_len = htons(frag_size + doffset); - iph->id = htons(id); - iph->check = 0; - iph->check = ip_fast_csum((unsigned char *) iph, iph->ihl); - th->seq = htonl(seq); - if (offset + doffset + frag_size < skb->len) - th->fin = th->psh = 0; - netif_rx(nskb); - offset += frag_size; - seq += frag_size; - id++; - } - - dev_kfree_skb(skb); -} -#endif /* LOOPBACK_TSO */ - /* * The higher levels take care of making this non-reentrant (it's * called with bh's disabled). -- 1.5.6.5.GIT