rc(8) parallel tasks

[Larry Maloney]

Awesome

Sent from my iPhone

> On Oct 2, 2015, at 9:16 AM, Cyril Vechera <cv at jet9.net> wrote:
> 
> Hi there.
> 
> We've got a small launcher script (~250 loc) for parallel services start/stop etc. It is used on our embedded systems and our users containers. And I've done a proof of concept for implanting it to the FreeBSD's standard /etc/rc for execution starting scripts in parallel. It gave me a boot time reduction of rc part from 27 to 7 seconds, mostly on eliminating jams for network or other long-latency resources waiting.
> 
> The launcher is written in pure POSIX shell and uses FIFOs (named pipes) as a mutexes for synchronization. So it is embedded into /etc/rc and /etc/rc.d preserving rc.subr preloading. As a primary requirement, it guarantees topological order (strict partial order) defined by dependencies. It requires only POSIX shell, FreeBSD or Linux kernel, mkfifo and a writeable file system. Due to last requirement, it can be run on the late stage or should be supplied by some kinf of writtable fs, ie tmpfs. The FreeBSD-integrated version uses standard rcorder annotations (REQUIRE, BEFORE and PROVIDE) and there's no need to change rc.d scripts
> 
> It's not a full init replacement or a kind of services supervision tool. It only starts or invokes a group of scripts in parallel with resolving and assuring execution in dependencies order.
> 
> Please take a look at the script and patch set for FreeBSD:
> 
> https://github.com/cvss/jet9-multitask-init/blob/master/jet9-multitask-init
> https://github.com/cvss/jet9-multitask-init/tree/master/examples/freebsd
> 
> 
> -- 
> Cyril Vechera
> 
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