[intelfx]

Goddamn, guys, stop repeating the same absurd.

kdbus is NOT ONLY about performance. It's about the lifetimes, the availiability in the early userspace, the new marshalling format, the new user bus concept, and so on, and so forth. It's about separating the transport (in the kernel) and the policy (in the userspace).

Most of these points can be achieved without putting the transport in the kernel, but some can not.

[tmd83]

Yeah right. No wonder I see people adding all sorts of adjective to the systemd proponent. I don't usually go hunting for sources and I only had Linus's comment about kdbus and performance. So I went to look for pottering's own word and here is a verbatime quote from the abstract of his presentation on kdbus

  D-Bus is a powerful design. However, being mostly a userspace solution its latency and throughput are not ideal. A full transaction consisting of method call and method reply requires 10 (!) copy operations for the messages passed. It is only useful for transfer of control messages, and not capable of streaming larger amounts of data.

So yeah he tried to sell performance as the big thing for his version of dbus IPC. I'm guessing he (and group) spent more time with dbus than linus and failed to find the actual cause of the performance issue or tried to hide it give more credence to kdbus. In both cases it makes it that much harder to trust their reasoning and conclusions.

I never said kdbus is ONLY about performance. But from what I'm reading they are not performance people but they think they are. The most dangerous people are those who don't know their own limitation or weakness. And your comment simply emphasise the practice of listening whats being said. So yeah given that I don't know dbus or ipc I have to trust your logic and you only make it hard to do so.

[digi_owl]

Seems the quote gets turned into a single long line in Firefox, and subsequently making the page extra wide...

[simoncion]

Strange. The quote is properly contained over here.

FF 40.0.3 on 32-bit Linux.

[simoncion]

If you haven't, you should go back and read all of the LKML discussion surrounding the request to merge kdbus into Linux 4.1. Perhaps I misunderstood something, but I got the distinct impression that several of the folks reviewing the code were concerned that kdbus pushes too much policy into the kernel.

LWN article: https://lwn.net/Articles/641275/

LKML thread: http://thread.gmane.org/gmane.linux.kernel/1930358

> It's about the lifetimes, the availiability in the early userspace...

Starting dbus in your initrd [0] makes it available to the system from before the first second your service start machinery is started. If you want dbus available to userspace in your initrd, make starting dbus the first thing you do after you load your initrd. Is there some particular reason why this doesn't meet the lifetime and availability requirements?

[0] Remember that the initrd is responsible for things like decrypting the rootfs. When you're in the initrd, your real system is often not even remotely ready to run.