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For anyone interested in high throughput/low latency networking, netmap ( http://info.iet.unipi.it/~luigi/netmap/ http://info.iet.unipi.it/~luigi/netmap/ ) look
by hosay123 14y ago
For anyone interested in high throughput/low latency networking, netmap ( http://info.iet.unipi.it/~luigi/netmap/ http://info.iet.unipi.it/~luigi/netmap/ ) looks really exciting in combination with a userspace TCP stack (e.g. unetstack). Pity I have no applications that could use it, would love to experiment.
- justincormack 14y agoNot sure I see why you would want to use it with a userspace network stack, I am sure at that point kernel networking is going to be faster. Netmap seems more useful for bridging, logging and UDP applications to me...
- hosay123 14y agoLocalizing packet processing significantly improves cache performance, in addition to avoiding copies and context switches. Receiving data from a socket almost always necessitates it being copied from a SKB to userspace memory, and prior to that from the driver's rx ring to a SKB. Grep for all references to 'cache' in http://lwn.net/Articles/169961/ http://lwn.net/Articles/169961/ which is Van Jacobsen's earlier work on a system of comparable design. Another (insanely more complex) implementation is http://www.openonload.org/ http://www.openonload.org/
- justincormack 14y agoAh thanks for that, hadn't realised that was a use case too, only started looking at this stuff the other day...
- ishbits 14y agoWonder if it would be useful for a user land network stack that paralleled what it could b