Toolchain WG - 2010-08-17 meeting minutes

Michael Hope michael.hope at linaro.org
Mon Aug 16 23:07:44 BST 2010


...are available here:
 https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-08-16

Activity reports are included below.

-- Michael

Attendees

    Name              Email                     IRC Nick
    Andrew Stubbs     andrew.stubbs at linaro.org  ams
    Julian Brown      julian at codesourcery.com   jbrown
    Loïc Minier       loic.minier at linaro.org    lool
    Matt Gretton-Dann ARM
    Matthias Klose    doko at canonical.com        doko
    Michael Hope      michael.hope at linaro.org   michaelh
    Peter Maydell     peter.maydell at linaro.org  pm215
    Ulrich Weigand    ulrich.weigand at linaro.org uweigand
    Yao Qi            yao.qi at linaro.org         yao

Agenda

  • Benchmarks
      □ ffmpeg (h.264), libmad (mp3), LAPACK, CoreMark, Dhrystone, and memcpy()
      □ EEMBC
      □ Methods of benchmarking
  • Patch tracking
      □ Minimum features
      □ Discovering upstream patches to backport
      □ Example version at http://ex.seabright.co.nz/helpers/patchtrack
      □ Ticket view at http://ex.seabright.co.nz/helpers/tickets
  • Upstream tracking
      □ Ubuntu tracks release+SVN. What should we do?
  • memcpy() and friends
      □ https://wiki.linaro.org/WorkingGroups/ToolChain/StringRoutines
      □ Copyright issues with EGLIBC
  • Hardware status
  • Creating blueprints
  • Connecting with other groups
  • Open tickets
      □ 616141 Backport the sync_* primitive fixes
      □ 590696 fix wrong use of objdump during cross build
      □ 600277 Backport ARM Cortex A9 scheduling changes
      □ 605059 Merge 4.4.5

Action Items from this Meeting

  • ACTION: Michael to think about synchronising Linaro releases with upstream
  • ACTION: Michael to organise a call with Matthias, Loic to continue the
    topic
  • ACTION: Michael to write up and email patch tracker mechanics for review
  • ACTION: Ulrich to add his time away to the Linaro calendar
  • ACTION: Michael and Ulrich to add GDB new features as blueprints to
    Launchpad
  • ACTION: Andrew to look into frequent runs of CSL benchmarks
  • ACTION: Michael to make sure Linaro has a FSF copyright assignment
    agreement

Action Items from Previous Meeting

  • DONE: Richard to ask the GCC developers on IRC what the status of 4.4.5 is
      □ Matthias talked with Jacob and they expect a release at the end of
        August
  • DONE: Andrew to merge 4.5.1 and the Firefox fix by 2010-08-17
  • DONE: Ulrich to ticket GDB items
  • DONE: Michael to understand whiteboards as a way of organising features

Minutes

Upstream patches:

  • Loic, Matthias, and Michael discussed tracking the upstream release branch
  • Upstream has a roughly three week cycle on patch releases
  • Matthias tracks this release branch and pulls in SVN as a patch into Ubuntu
  • Michael is concerned about the extra work, pulling a partial
      □ feature, catching a regression, fallout due to releasing something that
        upstream hasn't released,
  • Release branches are very stable. Chance of a regression is low
  • Better chance of getting a problem fixed upstream if caught early before
    the release
  • Loic: harder to track upstream
  • Loic: also harder to identify a Linaro release -
    FSF-4.4.4+svr12345+bzr6789...
  • Matthias spoke with Jacob in GCC. They expect a release at the end of
      □ August
  • Michael prefers basing on released versions only
  • Michael also wants to be able to reproduce any issues found in Ubuntu. Hard
    at the
      □ moment as Ubuntu runs Linaro plus a reasonably large set of patches

ts to be able

  • One approach: merge the day after the Linaro release. Gives the maximum
    time for
      □ testing. Still a month behind, still have Ubuntu GCC != Linaro GCC
  • Matthias
      □ Would continue to keep diff between Linaro and upstream
      □ Is doing changes upstream
      □ Would have to maintain those separately
      □ If there are release critical changes, would have to do them himself
  • Discussed different phase of Linaro GCC vs Ubuntu - the releases won't be
    in sync so there will always be a need for release critical fixes in Ubuntu
  • ACTION: Michael to think about synchronising Linaro releases with upstream
      □ Drift the Linaro release to be a week later than the upstream release
  • Andrew wasn't concerned. Noted that the release branches are really good
  • ACTION: Michael to organise a call with Matthias, Loic to continue the
    topic

Patch tracking:

  • Cortex-A5 changes are coming into Linaro
  • Michael did a quick show and tell on the patch tracker hack
  • ACTION: Michael to write up and email patch tracker mechanics for review

Other topics:

  • Ulrich is out on vacation next week
  • ACTION: Ulrich to add his time away to the Linaro calendar
  • ACTION: Michael and Ulrich to add GDB new features as blueprints to
    Launchpad
  • Michael noted that we use bzr for version control wherever possible,
    including for QEMU
  • Michael asked Andrew if we could start regular runs of the commonly used
    benchmark
  • ACTION: Andrew to look into frequent runs of CSL benchmarks
  • String routines
      □ Michael talked with upstream and they greatly prefer FSF+LGPL
      □ ACTION: Michael to make sure Linaro has a FSF copyright assignment
        agreement
  • Loic mentioned Valgrind patches
      □ Peter is interested in helping

Next meeting is a stand-up meeting on 2010-18-11 on the public code.

-- Julian Brown
	
== GCC 4.5 bugs in Launchpad ==

 * Attempted to reproduce bugs against Linaro GCC 4.5 in
Launchpad: issues #614184, #614185 and #614186. The last of these has
been closed as invalid by the submitter already, and the first two don't
seem to reproduce using a cross-compiler (i.e. using CS's build
machinery), nor with a natively-bootstrapped bzr head build (as of some
day last week). So, no real progress there.

== GCC 4.5 vectorization improvements ==

 * Started tracking down the causes of some failures in vect.exp:
pr43430-1.c failed because of missing vector comparison support. This
seemed relatively straightforward to implement using NEON instructions,
so I had a go at doing that. Similarly another test fails (vect-35.c)
because of missing support for widening/narrowing patterns, though I'm
still investigating a fix for that.

-- Andrew Stubbs
	
== Linaro GCC releases ==

 * Merged GCC 4.5.1 into the Linaro sources.
 * Respun the 4.5-2010.08 release.

== Linaro GCC 4.5 ==

 * Continued pushing SG++ patches into Linaro. I'm now most of the way
through these, but I had hoped to have had it done by now.

== Other ==

 * Lost a few hours to internet outages. An engineer came out and
changed all the connections, so hopefully that's solved the problem.
It seems the recent bad weather had got into the underground cables
between here and the street cabinet. It's fibre from there, so in
theory it must be local.

 * Took Wednesday as vacation.

-- Peter Maydell

Subject: [weekly][linaro] report week 32

RAG:
Red:   None
Amber: ARM legal OK for qemu contributions
Green: booted versatile+virtio kernel on qemu

Milestones: none as yet

Progress:

virtio-system:
 - identified which qemu patches give a qemu which can boot linaro
  alpha-3 on beagle emulation
 - built a kernel for 'versatile' flavour with virtio support
 - found some patches from qemu upstream which are needed for
  newer versatile kernels to boot
 - got my versatile kernel running on qemu with the linaro
  rootfs mounted via virtio
 - put various qemu changes/patches into a git tree, so (a) I
  know what I changed and (b) as an exercise in learning git

Issues: none

Plans:

virtio-system:
 - get versatile to boot *without* virtio for comparison
 - find an io benchmark and do some benchmarking
qemu-focused-kernel:
 - flesh out this blueprint

Absences:
None planned.

-- Chung-Lin Tang

== libffi VFP hard-float support ==

Testsuite fixes and final tuning before submitting. Had to port some
stuff from the GCC testsuite to let libffi's testsuite support a
dg-skip-if option, to skip some variadic function tests based on
compiler options (skip when -mfloat-abi=hard), and I am not a
DejaGNU/expect/Tcl expert...:P   Whole patch was submitted to main
libffi mailing list on Sunday, waiting for feedback.
(see http://sourceware.org/ml/libffi-discuss/2010/msg00153.html)

== This week ==
* See if any feedback on libffi patch.
* Start Linaro 4.5 EEMBC comparisons.
* Catch up on GCC work.

-- Yao Qi
	
== Linaro GCC ==

 * Pinged ARM backend maintainer for my patch to GCC PR45094.  Still
 no response.

 * Submit my patch on ARM target triplet in gcc-patches.  With Dan's
 help, got GCC write access.  Checked in my patch.

 * Update status of LP bugs.  Mark them as Fix Released since
 failures go away in gcc-linaro-4.4-2010.08-0.

== Linaro GDB ==

 * Search something about GDB from my brain, like gdb test,
 tcl/expect, ptrace/breakpointetc.  Fortunately, most of
 them are still there. :)

 * LP:615997 gdb.dwarf2/dw2-ref-missing-frame.exp failure
 Failure is caused by alignment of test case.  Sent a patch to
 gdb-patches, and revise it with Dan's help.

 * LP:615989 gdb.base/pending.exp
 Failure is caused by wrong code in .debug_line. Failure goes away
 when it is compiled by gcc-linaro-4.5-2010.08-1.
 Open a gcc bug LP:617384.

 * LP:615995 gdb.base/watch-vfork.exp : Watchpoint triggers after
vfork (sw) (timeout)
 Reproduce it on x86.  GDB is waiting endlessly between
TARGET_WAITKIND_FORKED and TARGET_WAITKIND_VFORK_DONE.  Looks like
child of debuggee hangs on 'signal'.

== This Week ==

 * Look into LP:615995 deeply, and other linaro gdb bugs.



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