Re: Speeding up dpkg, a proposal
On Thu, 2011-03-03 at 18:49:44 +0100, Raphael Hertzog wrote:
> On Thu, 03 Mar 2011, Phillip Susi wrote:
> > It would be much better to use aio to queue up all of the syncs at once,
> > so that the elevator can coalesce and reorder them for optimal writing.
> I'm not convinced it would help. You're welcome to try and provide a
> patch if it works.
> I'm not even convinced it's possible with the existing interfaces (but I
> have no experience with AIO). aio_fsync() is only usable with aio_write()
> and it's not possible to use lio_listio() to batch a bunch of aio_fsync().
Actually, this was discarded early on, as Linux does not implement
aio_fsync() for any file system. Also the interface is quite cumbersome
as it requires to keep state for each aio operation, and using SA_SIGINFO
(which is not yet available everywhere).