BPF: what's good, what's coming, and what's needed [LWN.net]

BPF: what's good, what's coming, and what's needed

Posted May 10, 2019 22:34 UTC (Fri) by Cyberax (✭ supporter ✭, #52523)
In reply to: BPF: what's good, what's coming, and what's needed by roc
Parent article: BPF: what's good, what's coming, and what's needed

The max number of instructions has been increased to 10^6. So I predict we'll get a backbranch instruction in about a year.

After all, a million instructions is already more than some subsystems can afford.

to post comments

Posted May 13, 2019 23:37 UTC (Mon) by atai (subscriber, #10977) [Link] (1 responses)

when will the kernel be written in BPF?

Posted May 14, 2019 0:30 UTC (Tue) by pizza (subscriber, #46) [Link]

I think we'll need a BPF compiler written in BPF first, as well as a BPF->C converter so the kernel can bootstrap itself..

Posted May 16, 2019 3:06 UTC (Thu) by naptastic (guest, #60139) [Link] (1 responses)

What's a "backbranch" instruction? I thought I knew all the flow control primitives...

Posted May 16, 2019 3:43 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Jump back if condition is fulfilled. It means that you can make loops with arbitrary number of iterations.