Toolchain WG - 2010-08-24 meeting minutes

Michael Hope michael.hope at linaro.org
Tue Aug 24 03:46:25 BST 2010


Please find the activity reports and minutes for Monday's meeting
below.  The minutes are also available at:
 https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-08-23

Minutes from the Wednesday and Friday standup calls are at:
 https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-08-18
 https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-08-20

-- Michael

Attendees

  • Name             Email                    IRC Nick
    Andrew Stubbs    andrew.stubbs at linaro.org ams
    Chung-Lin Tang   cltang at codesourcery.com  cltang
    Matthias Klose   doko at canonical.com       doko
    Michael Hope     michael.hope at linaro.org  michaelh
    Peter Maydell    peter.maydell at linaro.org pm215
    Richard Earnshaw richard.earnshaw at arm.com rearnshaw
    Yao Qi           yao.qi at linaro.org        yao

Agenda

  • 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
  • Upcoming release
      □ GCC 4.4
      □ GCC 4.5
      □ GDB
      □ Strings
  • 4.6 backport approach
  • Creating blueprints
  • Connecting with other groups

    Blueprint                          Assignee
    Initial delivery of Linaro GCC 4.4 ams
    Cross Compiler Packages            hrw

Action Items from this Meeting

  • ACTION: Chung-Lin to move the list of other backports out of the CSL wiki
    and into Linaro
  • ACTION: Michael to re-check with TSC that we can assign copyright but keep
    ability to relicense
  • ACTION: Yao to continue on GDB for a week then switch to investigation
  • ACTION: Peter to check into the state and progress of valgrind for the
    meeting on the 30th.

Action Items from Previous Meeting

Minutes

Tickets:

  • Went through the open tickets in the agenda
  • Andrew will backport the SMP changes, including the sync primitives
  • Andrew will backport the A9 changes
      □ Most of the changes should come through easily
      □ There is a write after write hazard
      □ Currently uses the new cost infrastructure
      □ Backport the cost infrastructure if it will be used further in the
        future

4.6 branch:

  • Andrew suggested starting a 4.6 branch after the start of stage 3
      □ Start landing patches early
      □ When FSF 4.6.0 comes out, we will have a corresponding Linaro 4.6.0
  • ACTION: Chung-Lin to move the list of other backports out of the CSL wiki
    and into Linaro

String routines:

  • Richard asked about the response
  • Michael had replies from Roland McGrath (http://sourceware.org/ml/
    libc-alpha/2010-08/msg00029.html) but not the wider gcc-sc
  • All other architectures are LGPL and FSF assigned
  • The current approach is to assign a particular version to glibc
  • Could cause a small maintenance problem in the future
  • Richard isn't sure that we can assign copyright of a particular version
  • ACTION: Michael to re-check with TSC that we can assign copyright but keep
    ability to relicense

4.6 backports:

  • Talked about the approach for backporting 4.6 features
  • Won't backport every single change as then Linaro 4.5 becomes FSF 4.6
  • Backport correctness fixes as the problem is found
  • Backport performance changes as they occur
  • Discussed how upstream could be tracked
      □ Notification of any CSL or ARM authered changes will come from them
      □ All changes are supposed to go through gcc-patches
      □ Andrew notes that gcc-cvs provides a filtered view of what actually
        landed
      □ At least monitor these lists and search for ARM|Thumb|NEON|XSCALE|
        Cortex|Coretx|VFP|Snapdragon|OMAP

Michael noted that IBM are interested in the ARM compiler and plan to get
involved soon.

Michael has asked again for A9 hardware. No news yet.

Future:

  • Would like to spend some time soon running invetigrations to spit out some
    blueprints
  • ACTION: Yao to continue on GDB for a week then switch to investigation
  • Andrew noted that there is one more person to come from CSL
  • Will ask that person to do investigation
  • Richard is keen to see the blueprints to check against what ARM is doing
      □ Michael asked for information about their planning process so that we
        can line things up

Valgrind:

  • Peter noted that the valgrind changes have been committed upstream
  • ACTION: Peter to check into the state and progress of valgrind for the
    meeting on the 30th.

Next meeting is a stand-up meeting on 2010-08-25 on the public code.

--- Andrew Stubbs
	
== GCC 4.5 ==

 * Continued pushing 4.5 patches to Linaro. I have now caught up with
current development I think.

 * Lots of discussion on the patch tracker. You'd think it was more
important than the compiler .... :(

== Upstream ==

 * Did before and after tests of the Coretex-A5 scheduler against
upstream HEAD. All seemed well (or at least, no worse) so I've posted
the patch upstream. No word back yet ....

--- Chung-Lin Tang
	
 == Hard-float ==
* Testing EEMBC softfp vs. hard-float calling convention performance numbers.

* The only conclusive result was that OAmark is 2%-3% faster,
presumably due to vector graphics-like code in that suite. May look
into other code (was suggested Cairo) to see if any gain in changing
to hard-float.

* Withdraw earlier comment on small improvements on Automark (was not
apparent after more experiment runs).

* Currently working to produce report files.

== Linaro GCC ==
* Looking at getting into GCC backport work this week.

--- Yao Qi

== Linaro GDB ==

 * LP:615997 gdb.dwarf2/dw2-ref-missing-frame.exp failure
 Patch is committed to gdb mainline.

 * LP:615999 gdb.gdb/selftest.exp failure
 Patch is committed to gdb mainline.

 * LP:615995 gdb.base/watch-vfork.exp : Watchpoint triggers after
vfork (sw) (timeout)
 With Pedro's help, got to know the failure of this case on arm and
x86 are different.  Created a patch as Ulrich suggested, and it works
on 2.6.32, while fails in a different way on 2.6.35.  Failure is
caused by debuggee process is killed by a SIGTRAP.  Still no clue why
that can happen.

== Linaro GCC  ==

 * My patch to PR45094 is approved, and checked in to mainline.

== This Week ==

 * Fix LP:615995 and other linaro gdb bugs.

--- Ulrich Weigand

== GCC ==

 * Collected and wrote up suggestions for future GCC work

== GDB ==

 * Opened Launchpad bugs for known GDB problems and testsuite failures
 * Investigated bug #620595 (gdb.threads/threxit-hop-specific.exp failure)
 * Fixed bug #615998 (gdb.gdb/observer.exp failures) in mainline and 7.2
 * Worked on upstream fix for #620595 (gdb.threads/threxit-hop-specific.exp
failure)
 * Analyzed bug #620611 (Unable to backtrace out of vector page 0xffff0000)

== Infrastructure ==

 * Continued working with our order&control team to acquire IGEPv2 boards

--- Peter Maydell

RAG:
Red:   None
Amber: ARM legal OK for qemu contributions still pending
Green: we have approval for laptops for linaro secondees

Milestones:
                              | Planned    | Estimate   |  Actual  |
finish virtio-system           | 2010-08-27 | 2010-08-27 |          |

Progress:

virtio-system:
 - got my versatile kernel/qemu running with virtio disk and network
  versus non-virtio
 - ran some basic benchmarking (bonnie++ for disk, tbench for net).
  Disk is faster with virtio, but strangely networking is not!
 - tried an upstream qemu too -- net virtio still slower
 - built a realview kernel in preparation for testing Arnd's
  PCI patches on hardware

qemu-focused-kernel:
 - some research into which ARM dev boards support PCI in
  hardware, kernel and qemu, to try to find a good choice for
  basing a qemu-focused kernel on

merge-other-branches:
 - started compiling list of qemu branches for possible consolidation

Issues: the intersection of (recent ARM hardware) (PCI support)
and (supported in qemu) looks suspiciously like the empty set.

Plans:
virtio-system:
 - borrow some versatile or realview hardware and test Arnd
  Bergmann's PCI patches
 - make a start on writing up the config/benchmark results
qemu-focused-kernel:
 - flesh out this blueprint
valgrind:
 - try to build an ARM valgrind from upstream's thumb branch

Absences:
Friday 5 November and 20 other days in this calendar year



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