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Re: [Qemu-devel] Re: [PATCH][RFC] Refactor AIO to allow multiple AIO imp
Re: [Qemu-devel] Re: [PATCH][RFC] Refactor AIO to allow multiple AIO implementations
Thu, 11 Sep 2008 14:28:31 +0100
Gerd Hoffmann wrote:
> > (I think the best
> > route is a thread-pool based implementation).
> Not sure about that. linux-aio would have the advantage that the kernel
> knows about all the requests in flight and probably can do a better job
> on I/O ordering and scheduling then. But once we can have multiple
> different implementations we can just try ;)
Won't posix-aio give the same info to the kernel when used with a
sufficiently avante-garde Linux distro?
I'm under the impression that linux-aio is better in every way, as
I think Anthony Liguori posted a while back:
>>> Threads are a poor substitute for a proper AIO interface.
>>> linux-aio gives you everything you could possibly want in an
>>> interface since it allows you to submit multiple vectored operations
>>> in a single syscall, use an fd to signal request completion,
>>> complete multiple requests in a single syscall, and inject barriers
>>> via fdsync.
But knowing about request in flight, I/O ordering etc. seem equally
available via posix-aio on a distro where that calls linux-aio
(i.e. not the Glibc implementation).