On Tue, Feb 06, 2007 at 03:56:14PM -0800, Davide Libenzi wrote:
> Async syscall submissions are a _one time_ things. It's not like a live fd
> that you can push inside epoll and avoid the multiple O(N) passes.
> First of all, the amount of syscalls that you'd submit in a vectored way
> are limited. They do not depend on the total number of connections, but on
I regularly see apps that want to submit 1000 I/Os at once.
Every submit. But it's all against one or two file descriptors. So, if
you return to userspace, they have to walk all 1000 async_results every
time, just to see which completed and which didn't. And *then* go wait
for the ones that didn't. If they just wait for them all, they aren't
spinning cpu on the -EASYNC operations.
I'm not saying that "don't return a completion if we can
non-block it" is inherently wrong or not a good idea. I'm saying that
we need a way to flag them efficiently.
Joel
--
Life's Little Instruction Book #80
"Slow dance"
Joel Becker
Principal Software Developer
Oracle
E-mail: [email protected]
Phone: (650) 506-8127
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
