Mail Archives: cygwin/2006/08/03/13:22:34
On Thu, 3 Aug 2006, Corinna Vinschen wrote:
> On Aug 3 01:54, Eric Blake wrote:
> > > >I'm really seeing the non-optimized cygwin cp behaviour causing bad
> > > >reputation, which could be easily patched and maybe even accepted
> > > >upstream. Who knows. Eric what do think? Would it be worthful to think
> > > >about?
> >
> > I don't really want to maintain a Windows API patch, and doubt that
>
> Good.
>
> > it would be accepted upstream. Now if there were something more
> > POSIX-y that we could do to speed things up, such as posix_fadvise,
>
> posix_fadvise can't be implemented nicely, AFAICS. The POSIX semantics
> require an already opened file and the advice is given for an offset and
> a length. The Windows semantics only allow to give the advice for the
> whole file, and only switching between FILE_SEQUENTIAL_ONLY or "normal",
> using ZwSetInformationFile. By re-opening the file using ZwOpenFile it
> would also be possible to toggle the FILE_RANDOM_ACCESS flag. Still,
> it's always for the whole file, not for an area giving offset and length.
Theoretically, it's possible to implement posix_fadvise only for offset=0
and length=<length-of-file>, and have it fail with EINVAL otherwise...
While technically not POSIX-compliant, it would still allow for better
implementation of things like copy...
Igor
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