ATTN: OCaml 4.03 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Richard W.M. Jones]

OCaml 4.03 has been out for a while.

I'm intending to add it to Fedora Rawhide once a side tag has been
created: https://fedorahosted.org/rel-eng/ticket/6486

This will require rebuilding every OCaml package, which I normally do
using a script, but probably there will be manual rebuilds necessary
too.

A few issues that may affect people:

(1) There is a new ppc backend upstream, and I intend to switch to this.

For years we have maintained our own out-of-tree ppc64 & ppc64le
backends.  I want to switch to the upstream ppc backend (which
supports, in theory, ppc 32 bit, ppc64 and ppc64le).  However when I
actually tried this I found it to be rather buggy, it couldn't even
compile many basic OCaml packages.  This time I intend to switch, and
we'll deal with the bugs.

(2) There is a new s/390x backend upstream.  This should enable us to
compile all s/390x packages as native code.

It also means that all supported architectures (yes, even riscv64)
will support native compilation for OCaml.

(3) The real reason I'm doing this now is because partners have asked
us to update the OCaml compiler in RHEL 7.4.  This will be a binary
ABI break -- it's unfortunately unavoidable -- and will require all
OCaml-using programs to be recompiled, and of course that will affect
CentOS and any other RHEL derivatives.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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ATTN: OCaml 4.04 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Richard W.M. Jones]

On Tue, Oct 18, 2016 at 02:04:22PM +0100, Richard W.M. Jones wrote:
>  OCaml 4.03 has been out for a while. 
Since OCaml 4.04.0 was released last Friday, we rebased to 4.04.0.

This is now ready to test.  If you have Rawhide + some package that
needs OCaml, then add the following repository and you can pull down
the new OCaml version to test against:

$ cat /etc/yum.repos.d/tmp-f26-ocaml.repo
[f26-ocaml]
name=f26-ocaml
baseurl=https://kojipkgs.fedoraproject.org/repos/f26-ocaml/latest/$basearch/
enabled=0
gpgcheck=0

>  A few issues that may affect people:
>  
>  (1) There is a new ppc backend upstream, and I intend to switch to this.
>  
>  For years we have maintained our own out-of-tree ppc64 & ppc64le
>  backends.  I want to switch to the upstream ppc backend (which
>  supports, in theory, ppc 32 bit, ppc64 and ppc64le).  However when I
>  actually tried this I found it to be rather buggy, it couldn't even
>  compile many basic OCaml packages.  This time I intend to switch, and
>  we'll deal with the bugs. 
The good news is that the new POWER backend in 4.04 is very stable.
We haven't found any problems at all, and compiling for ppc64le
actually revealed undefined behaviour in a C library:

  https://bugzilla.redhat.com/show_bug.cgi?id=1392247#c3

For ppc64le you will require POWER8.  Running on POWER7 will cause
random segfaults because various vector instructions are used that
weren't available in POWER7.

>  (2) There is a new s/390x backend upstream.  This should enable us
> to
>  compile all s/390x packages as native code.
>  
>  It also means that all supported architectures (yes, even riscv64)
>  will support native compilation for OCaml. 
Neither s390x nor riscv64 are enabled at the moment, but I hope to get
that done in the next few days or weeks.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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ATTN: OCaml 4.04 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Peter Robinson]

On Tue, Nov 8, 2016 at 9:06 AM, Richard W.M. Jones <rjones(a)redhat.com&gt; wrote:
>  On Tue, Oct 18, 2016 at 02:04:22PM +0100, Richard W.M. Jones wrote:
> > OCaml 4.03 has been out for a while.
>
>  Since OCaml 4.04.0 was released last Friday, we rebased to 4.04.0.
>
>  This is now ready to test.  If you have Rawhide + some package that
>  needs OCaml, then add the following repository and you can pull down
>  the new OCaml version to test against:
>
>  $ cat /etc/yum.repos.d/tmp-f26-ocaml.repo
>  [f26-ocaml]
>  name=f26-ocaml
>  baseurl=https://kojipkgs.fedoraproject.org/repos/f26-ocaml/latest/$basearch/
>  enabled=0
>  gpgcheck=0
>
> > A few issues that may affect people:
> >
> > (1) There is a new ppc backend upstream, and I intend to switch to this.
> >
> > For years we have maintained our own out-of-tree ppc64 & ppc64le
> > backends.  I want to switch to the upstream ppc backend (which
> > supports, in theory, ppc 32 bit, ppc64 and ppc64le).  However when I
> > actually tried this I found it to be rather buggy, it couldn't even
> > compile many basic OCaml packages.  This time I intend to switch, and
> > we'll deal with the bugs.
>
>  The good news is that the new POWER backend in 4.04 is very stable.
>  We haven't found any problems at all, and compiling for ppc64le
>  actually revealed undefined behaviour in a C library: 
Good news on the stability.

>    https://bugzilla.redhat.com/show_bug.cgi?id=1392247#c3
>
>  For ppc64le you will require POWER8.  Running on POWER7 will cause
>  random segfaults because various vector instructions are used that
>  weren't available in POWER7. 
IBM don't support ppc64le on Power7 anyway, we explicitly use Power8
compiler flags on LE so it's a moot point.

> > (2) There is a new s/390x backend upstream.  This should enable
> us to
> > compile all s/390x packages as native code.
> >
> > It also means that all supported architectures (yes, even riscv64)
> > will support native compilation for OCaml.
>
>  Neither s390x nor riscv64 are enabled at the moment, but I hope to get
>  that done in the next few days or weeks. 
OK, well just update the rel-eng ticket when you want it merged back
into rawhide.

ATTN: OCaml 4.04 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Richard W.M. Jones]

On Tue, Nov 08, 2016 at 09:11:01AM +0000, Peter Robinson wrote:
>  OK, well just update the rel-eng ticket when you want it merged back
>  into rawhide. 
This will hopefully be later today or tomorrow.  I've got
a few packages that I'm still debugging.

Will update the ticket when ready.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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ATTN: OCaml 4.04 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Dan Horák]

On Tue, 8 Nov 2016 09:13:32 +0000
"Richard W.M. Jones" <rjones(a)redhat.com&gt; wrote:

>  On Tue, Nov 08, 2016 at 09:11:01AM +0000, Peter Robinson wrote:
>  > OK, well just update the rel-eng ticket when you want it merged back
>  > into rawhide.
>  
>  This will hopefully be later today or tomorrow.  I've got
>  a few packages that I'm still debugging. 
wouldn't it be better to enable the s390x native generator before
merging? Or do you plan a second round of bootstrapping? Let me know if
you want access to a s390x machine.


		Dan
 
> Will update the ticket when ready.
> 
> Rich.
> 
> -- 
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones Read my programming and
> virtualization blog: http://rwmj.wordpress.com virt-p2v converts
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ATTN: OCaml 4.04 in Rawhide, could affect POWER, s/390, RHEL 7.4, CentOS 7.4

[Richard W.M. Jones]

On Tue, Nov 08, 2016 at 02:15:26PM +0100, Dan Horák wrote:
>  On Tue, 8 Nov 2016 09:13:32 +0000
>  "Richard W.M. Jones" <rjones(a)redhat.com&gt; wrote:
>  
>  > On Tue, Nov 08, 2016 at 09:11:01AM +0000, Peter Robinson wrote:
>  > > OK, well just update the rel-eng ticket when you want it merged back
>  > > into rawhide.
>  > 
>  > This will hopefully be later today or tomorrow.  I've got
>  > a few packages that I'm still debugging.
>  
>  wouldn't it be better to enable the s390x native generator before
>  merging? Or do you plan a second round of bootstrapping? 
It should be a matter of enabling the s390x backend.  That will
require rebuilding all the packages, but crucially their dependencies
won't change so there won't be broken deps during that rebuild.
(That's the theory anyway ...)

>  Let me know if you want access to a s390x machine. 
Yes please, I'm ready to work on this bit now.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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