On Tue, Dec 26, 2000 at 02:36:01PM -0800, Rajagopal Ananthanarayanan wrote:
> "David M. Grimes" wrote:
> >
> > All,
> >
> > I have just recently obtained, successfully built, and am experimenting with
> > the kaio patches (1.3 for 2.4.0-test10). My questions are related to the
> > use of raw devices with kaio, and specifically, to the comment on the KAIO
> > homepage which says:
> >
> > "KAIO is also integrated to work well with Raw I/O, another
> > feature availabe with SGI Linux Environment 1.1 or as a patch
> > from this web site."
> >
> > I could only find the Raw I/O (SCSI SGI patches) for 2.2.13, and 2.4.0+ has
> > the Tweedie char/raw.c raw devices by default. So, are the SGI patches
> > integrated in another set of patches? Is the native stuff as good now, and
> > the patches are no longer being maintained? If not, can they be made
> > available so they are suitable for the same kernel version as kaio?
>
> The 2.4 raw i/o, however, does not provide seperate
> inititate_io and wait_io functions. Thus, the number
> of outstanding raw i/o will be limited by the number
> of slave threads. Also, the 2.4 raw I/O uses bufferheads
Do you know if there is any intent to make the SGI SCSI patches available
for 2.4 kernels? From the documentation provided with KAIO, it appears that
when using kaio on files on a ext2 filesystem you get asynchrony independant
of the slave threads. Is this true? If not, how can I achieve true
asynchronous I/O without being limited by the number of slave threads?
If the SGI SCSI pathches are not (and cannot be) availble for 2.4 kernels,
can the kaio-1.3 be produced against a 2.2.13 kernel so it can be used with
the SGI SCSI patches?
> to queue the I/O as compared the SGI SCSI patch which
> directly translates the I/O into a scsi scatter-gather list.
Ultimately, this is what I am trying to do. I guess I could get by with
large files on an ext2 filesystem, but I'd really prefer to use raw SCSI I/O.
Thanks in advance for any help,
David Grimes
Senior Software Architect
AppliedTheory Corporation
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