Messages in this thread |  | | From | Andi Kleen <> | Subject | Re: [PATCH 4 of 4] Introduce aio system call submission and completion system calls | Date | Wed, 31 Jan 2007 18:21:59 +0100 |
| |
On Wednesday 31 January 2007 18:15, Zach Brown wrote: > > On Jan 31, 2007, at 12:58 AM, Andi Kleen wrote: > > > Do you have any numbers how this compares cycle wise to just doing > > clone+syscall+exit in user space? > > Not yet, no. Release early, release often, and all that. I'll throw > something together.
So what was the motivation for doing this then? It's only point is to have smaller startup costs for AIO than clone+fork without fixing the VFS code to be a state machine, right?
I'm personally unclear if it's really less work to teach a lot of code in the kernel about a new thread abstraction than changing VFS.
Your patches don't look that complicated yet but you openly admitted you waved away many of the more tricky issues (like signals etc.) and I bet there are yet-unknown side effects of this too that will need more changes.
I would expect a VFS solution to be the fastest of any at least.
I'm not sure the fibrils thing will be that much faster than a possibly somewhat fast pathed for this case clone+syscall+exit.
-Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |