Re: Implementing aio_* and lio_* (async i/o) on Cygwin

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

Hi Mark,

On Mar 28 22:57, Mark Geisert wrote:
> Corinna Vinschen wrote:
> > On Mar 19 22:53, Mark Geisert wrote:
> > > Regardless of which file the code is in, I was thinking I should copy
> > > syscalls.cc's pread() contents into aio_read(), for example, to start with.
> > > Then add extra param(s) as needed to the fhandler method call as you
> > > suggested.
> > 
> > That's definitely ok.  When I was talking about pread/pwrite in our
> > preliminary discussion on cygwin-patches, I was always talking about the
> > fhandler_disk_file::pread and fhandler_disk_file::pwrite methods in
> > fact, not the syscalls of the same name.  I'm sorry I was unclear there :}
> [...]
> > Looks like you're on the right track, just go ahead.  We can fix the
> > finer details later.
> 
> OK, I've posted a 3-part patch set to cygwin-patches.  This is still a WIP
> so it doesn't yet include what's been decided above.  It currently queues
> async ops to cygthread worker threads.
> 
> I plan to update aio_read() and aio_write() to try to launch async ops
> inline, and only if they fail with ESPIPE would they be queued for worker
> thread action.  (E.g., ops on sockets or other devices without pread/pwrite
> support.)
> 
> I think parts 1 and 2 of the patch set are essentially finished, unless
> there are issues to be corrected.  But part 3 will need some more work done.
> Thanks,

Thank you!  I'm a bit low on available time ATM so please be patient.
I'll check your patch as time permits.

A word in terms of your commit messages.  Just providing the fact in the
commit header is a bit low on details.  Don't be shy to improve your
commit messages with some details, what you did, why you did it, what to
look for.

Some testcase (here on cygwin-developers, not as patch) would be
nice, too.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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