Bonjour, Le papier est interessant pour ceux qui font du routage ou de l'analyse de traffic en soft :
http://queue.acm.org/detail.cfm?id=2103536 Comme quoi dépoussierer quelques vieilleries dans les API :). Sincèrement, Laurent http://tetaneutral.net -------- Forwarded Message -------- From: Luigi Rizzo <ri...@iet.unipi.it> To: bl...@lists.bufferbloat.net Subject: [Bloat] high speed networking from userspace Date: Tue, 13 Mar 2012 15:29:35 +0100 Hi, Dave mentioned me the thread about netmap on this list, to which i just subscribed. Some of the posts are referring to Van Jacobson's "network channels" and to previous experiments or implementations dating back to 2006 e.g. http://www.ioremap.net/taxonomy/term/6 I am glad to see that there were previous attempts at addressing the problem. However before dismissing things as 'done before' i would suggest some performance comparison. For netmap what i can offer at the moment is some data comparing raw packet I/O performance with various sockets families, libpcap, PACKET_TX_RING on linux, and even the in-kernel packet generator in Linux. See for instance see a recent ACM Queue paper (freely accessible), fig.4 and 5 http://queue.acm.org/detail.cfm?id=2103536 In all these cases netmap is one order of magnitude or more faster than the alternatives. Unfortunately I cannot find any actual performance data on netchannel except those from the LCA'06 Van Jacobson slides, where they show about 2x speedup over the host stack. The original netchannel site reports 404 on all links, e.g. http://tservice.net.ru/~s0mbre/blog/2006/10/26#2006_10_26 If someone had some performance data or examples of technologies that work well i would be grateful to see them. Comparing netmap with VJ network channels: - both try to remove skbuf, and move processing out of the interrupt/kernel bottom half and into the user thread (above or below the userland/kernel barrier) to improve cache locality and for other good reasons. These two are key ideas for improving performance, which for instance PF_PACKET does not use (convenient as it does not need driver modifications, but there is a huge cost in performance.) I cannot easily tell whether netchannel implements any of these features: - userspace visible buffers (saves a memory copy and data access which may be helpful for packet forwarding apps where you only look at part of the payload) - poll-able file descriptor (useful to build a pcap layer on top of the packet I/O framework) cheers luigi _______________________________________________ Bloat mailing list bl...@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat --------------------------- Liste de diffusion du FRnOG http://www.frnog.org/