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Monday 13 February 2017

What happened to my vlan?

A long term goal of the effort I'm driving to unlock OpenBSD's Network Stack is obviously to increase performances. So I'd understand that you find confusing when some of our changes introduce performance regressions.

It is just really hard to do incremental changes without introducing temporary regressions. But as much as security is a process, improving performance is also a process. Recently markus@ told me that vlan(4) performances dropped in last releases. He had some ideas why but he couldn't provide evidences. So what really happened?

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Friday 13 January 2017

A story of if_get(9)

During the l2k15 hackathon, we enjoyed putting a lot of if_get(9) all over the network stack. Then more recently we started removing them. I even briefly explained why we should try to avoid using this API. All of this can be confusing, so let me tell you a story. A story of garbage collection inside the kernel.

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Friday 17 June 2016

ART single thread performances

ART has been the default routing table backend in OpenBSD for some months now. That means that OpenBSD 6.0 will no longer consult the 4.3 BSD reduced radix tree to perform route lookups.

The principal motivation for adopting a new tree implementation can be explained in three letters: SMP.

I'll describe in a different context why and how ART is a good fit in our revamp of OpenBSD network stack. For the moment, let's have a look at the single-thread performances of this algorithm in OpenBSD -current.

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