On: Rob Pike discovers sendfile(2)

[mfukar]

Rob Pike should read about D-Bus in the kernel[1], next. Maybe he'll have some comments. No, I mispoke, I think he'll definitely have some comments.

[1] http://git.collabora.co.uk/?p=user/alban/linux-2.6.35.y/.git...

[wmf → mfukar]

There is a legitimate debate about the performance vs. elegance tradeoff that sendfile represents. Putting D-Bus in the kernel is just a bad idea.

[mfukar → wmf]

I disagree. I think it's nothing but a good idea compared to its current state, for the following reasons:

- IPC in userspace is insecure, and currently easily subverted by rootkits.

- When a system is under heavy load, the dbus daemon becomes a choke point for scheduling. "Spammy" processes can prevent messages from reaching higher priority processes.

- It is a lifesaver for embedded devices with poor multitasking capabilities. Think about ucLinux.

- It's not for everyone. It's like PF_RING for packet capturing.

- It makes sense not only for performance, but also reliability.

- Even though DBus can be improved in several other aspects, I think it's nice that someone sat down and wrote this instead of bikeshedding on some website.

2c