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What does moving the networking stack into userland accomplish?
by saosebastiao 12y ago
What does moving the networking stack into userland accomplish?
- wmf 12y agoAvoiding system call overhead and the GPL. I suspect most of the performance improvement has nothing to do with being in userspace, but people use that term as a shorthand to refer to a whole collection of techniques like polling, batching, not performing routing/filtering, etc.
- SEJeff 12y agoClose, but it really has nothing at all to do with the GPL. It has to do with reducing context switches (from userspace to kernelspace) and reducing hardware interrupts. When the name of the game is latency, context switches really hurt you. Batching is awful for latency, and great for throughput fyi. In fact, openonload[1], and vma[1], 2 of the most common vendor provided kernel offload tools in use are both open source! [1] http://www.openonload.org/ http://www.openonload.org/ [2] http://www.mellanox.com/page/software_vma?mtag=vma http://www.mellanox.com/page/software_vma?mtag=vma