Monday 28th Feb 2011

This month's meetings

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Attendees

Agenda

  • Review action items from last meeting
  • A new 'Using' section on the wiki - WorkingGroups/ToolChain/Using/GCCNative

  • Versatile Express QEMU status
  • libunwind is approved
  • gmpbench run
    • 15 % headroom
    • ARMv7 is 6 % slower than ARMv5
    • NEON is neutral
  • Next steps on benchmarks
  • Next weeks release
    • GCC outstanding merges
    • QEMU
    • GDB
    • 723185 -marm -mneon constraint fault

    • 721023 -Os i686 ICE

    • 705689 Qt bad code in qatomic

    • 709453 wrong code generated in 179.art

    • 711819 ICE in push_minipoll_fix

    • 714921 Excessive memory usage when compiling QEMU

  • Possibly:
    • 724987: discourage use of NEON on the A8

    • 628907: function/jump alignment performance patch

    • 714921: excessive memory usage while compiling QEMU

Action Items from this Meeting

  • ACTION: 721023 Andrew to follow up inside CSL and upstream to get a fix for next release

  • ACTION: 711819 Andrew to see if it exists in gcc-linaro and take next step

  • ACTION: 714921 Richard S to own, report upstream if need be

  • ACTION: if anyone has experience in prioritising benchmark regressions, please contact Michael

Minutes

New section on wiki:

  • Added, see agenda for a link

VExpress and QEMU:

  • Have a bunch of patches that Peter is happy with
  • Started sending things upstream, hasn't been reviewed yet
  • Will merge into qemu-linaro, will be in 2011.03
  • Status
    • Boots standard Linaro kernel
    • Has video, MMC, networking
    • Keyboard and mouse hasn't been tested but should work
  • What's needed to finish off?
    • Test keyboard and mouse
    • Don't bother with USB support

libunwind:

  • Have TSC approval now, Michael volunteered Ulrich to help

gmpbench:

  • Finished running
  • Shows that we're ~10 % behind the best
  • ARMv5 is also better than ARMv7

Next weeks release:

  • Merge request backlog
  • Andrew: not as many as you think
  • Some are 4.6 only, some are equivalent
  • Five fixes to GCC 4.5
  • Will do all three releases including 4.6
  • Why 4.6?
    • Allows external testing
    • Gives Marcin something to pick up
    • Gives Matthias something to base off
    • Michael: worried about the overhead, but 4.4 won't have any changes

QEMU release:

  • Producing is straight forward
  • Dave: will test the release
  • How to share the pre-release?
    • Andrew uses Google Docs
    • Gives you 2 GB of storage
    • Peter will use that

GDB release:

  • Ulrich is absent, Michael will follow up

Reviewing tickets:

  • 723185: Chung-Lin thinks there is a patch inside CSL, hasn't been sent upstream yet
  • 721023: -Os on i686 only, is caused by the shrink wrapping
    • Michael: happy to leave
    • ACTION: Andrew to follow up inside CSL and upstream to get a fix for next release
  • 705689
    • Seems to be exposed by our 4.5 only
    • Hasn't sent upstream yet as the fault hasn't been exposed
    • Richard E: should send as it is latent
  • 709453
    • What to do next? Revert? Fix? Seems to have petered out
    • Andrew: will revert for this one
    • Don't have the proper way to do it
    • Chung-Lin: seems to be a win for A8, not for A9
    • Michael: revert and ignore
    • Chung-Lin will own the actual fix
  • 711819
    • Ramana has reviewed
    • Does this exist in gcc-linaro-4.5?
      • If the patch was backported, then yes
      • ACTION: Andrew to see if it exists in gcc-linaro and take next step
  • 714921
    • Excessive memory usage
    • Turning on -fno-var-tracking works around it
    • Richard S: may be a patch upstream
    • ACTION: Richard S to own, report upstream if need be

Benchmarks:

  • Michael summarised last week's discussion re: getting down to tickets
  • Well educated guess
  • ACTION: if anyone has experience in prioritising benchmark regressions, please contact Michael

WorkingGroups/ToolChain/Meetings/Archive/2011-02-28 (last modified 2013-08-30 11:48:26)