[Vm-dev] it's amazing to me...

[Eliot Miranda]

Hi Dave,

On Mon, Oct 19, 2020 at 12:14 PM David T. Lewis <lewis at mail.msen.com> wrote:

>
> On Mon, Oct 19, 2020 at 10:17:12AM -0700, Eliot Miranda wrote:
> >
> > to be able to evaluate
> >     ByteArray new: 8 * 1024 * 1024 * 1024
> > and all it takes is a few seconds.  No drama.
> >
> > Now to see if I can save and restore an 8Gb image with the new non-stdio
> > unix file support.
>
> I might have missed something, but does this mean that you have implemented
> file I/O at the file descriptor level as opposed to the FILE* level for
> Unix?


Only for image read/write, not for general file i/o.  Though that shouldn't
be difficult and I may get to soon.  But I take Tim's suggestion of
grouping the file pointer and the read/write data in one as a good one, and
so would like to use pread/pwrite which provide this functionality.

> I have always wondered which approach would give the best real-world
> performance, and my guess was that the approach that Andreas used for the
> Windows VM (HANDLE aka file descriptor level) is probably better overall.
>

Yes, it appears to be faster.  The only complication is having to chunk
reads/writes (as happens on Win32 for the same reason) because read/write
don't like > 2Gb-1 (the max positive signed 32-bit value).

> Dave
>

_,,,^..^,,,_
best, Eliot
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