* zero copy with PACKET_MMAP @ 2014-02-27 6:40 ratheesh kannoth 2014-02-27 9:58 ` Daniel Borkmann 0 siblings, 1 reply; 3+ messages in thread From: ratheesh kannoth @ 2014-02-27 6:40 UTC (permalink / raw) To: netdev, linux-net Hi , The link https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt talks about achieving zero copy. But i find a deep packet copy ( of length snaplen= skb->len ) here http://lxr.free-electrons.com/source/net/packet/af_packet.c#L1841. Is there anything missing/wrong in my understanding ? Thanks, Ratheesh ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: zero copy with PACKET_MMAP 2014-02-27 6:40 zero copy with PACKET_MMAP ratheesh kannoth @ 2014-02-27 9:58 ` Daniel Borkmann 0 siblings, 0 replies; 3+ messages in thread From: Daniel Borkmann @ 2014-02-27 9:58 UTC (permalink / raw) To: ratheesh kannoth; +Cc: netdev, linux-net On 02/27/2014 07:40 AM, ratheesh kannoth wrote: ... > https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt > talks about achieving zero copy. But i find a deep packet copy ( of > length snaplen= skb->len ) here > http://lxr.free-electrons.com/source/net/packet/af_packet.c#L1841. > > Is there anything missing/wrong in my understanding ? The zero-copy is between user and kernel space. ^ permalink raw reply [flat|nested] 3+ messages in thread
[parent not found: <CAGZFCEF0zwQbNYU6yH8i=ebnhtVFeJRA0_XVDvgJ4O0Z5ietHw@mail.gmail.com>]
* Fwd: zero copy with PACKET_MMAP [not found] <CAGZFCEF0zwQbNYU6yH8i=ebnhtVFeJRA0_XVDvgJ4O0Z5ietHw@mail.gmail.com> @ 2014-02-27 7:28 ` ratheesh kannoth 2014-02-27 17:10 ` Jeff Haran 0 siblings, 1 reply; 3+ messages in thread From: ratheesh kannoth @ 2014-02-27 7:28 UTC (permalink / raw) To: kernelnewbies Hi , The link https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt talks about achieving zero copy. But i find a deep packet copy ( of length snaplen= skb->len ) here http://lxr.free-electrons.com/source/net/packet/af_packet.c#L1841. Is there anything missing/wrong in my understanding ? Thanks, Ratheesh ^ permalink raw reply [flat|nested] 3+ messages in thread
* zero copy with PACKET_MMAP 2014-02-27 7:28 ` Fwd: " ratheesh kannoth @ 2014-02-27 17:10 ` Jeff Haran 0 siblings, 0 replies; 3+ messages in thread From: Jeff Haran @ 2014-02-27 17:10 UTC (permalink / raw) To: kernelnewbies > -----Original Message----- > From: kernelnewbies-bounces at kernelnewbies.org [mailto:kernelnewbies-bounces at kernelnewbies.org] On Behalf Of ratheesh > kannoth > Sent: Wednesday, February 26, 2014 11:28 PM > To: kernelnewbies at kernelnewbies.org > Subject: Fwd: zero copy with PACKET_MMAP > > Hi , > > The link > > https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt > talks about achieving zero copy. But i find a deep packet copy ( of > length snaplen= skb->len ) here > http://lxr.free-electrons.com/source/net/packet/af_packet.c#L1841. > > Is there anything missing/wrong in my understanding ? > > > Thanks, > Ratheesh It's "zero copy" in that it is not necessary to copy the contents of the kernel resident socket buffer to user space in order for user space to read it. But you are not missing anything. There is still a copy involved in order to copy the packet to the socket ring buffer. Jeff Haran ^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-02-27 6:40 zero copy with PACKET_MMAP ratheesh kannoth
2014-02-27 9:58 ` Daniel Borkmann
[not found] <CAGZFCEF0zwQbNYU6yH8i=ebnhtVFeJRA0_XVDvgJ4O0Z5ietHw@mail.gmail.com>
2014-02-27 7:28 ` Fwd: " ratheesh kannoth
2014-02-27 17:10 ` Jeff Haran
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