Andrew Stubbs

Upstream patched requiring review

Chung-Lin Tang

Chung-Lin Tang to linaro-toolcha., gnu-linaro-too.

show details May 30 (2 days ago)

Last week

  • Investigated the CoreMark numbers posted by Michael Hope, mainly the oddities of a significant Linaro 4.6 regression versus FSF 4.6. Later verified to be a false alarm.

  • Pushed a merge of some of my upstream CoreMark patches to Linaro 4.6.

  • Did archeology for PR42017. Traced some history of the ARM prologue from 2000 to 2007 (DF branch), posted upstream. Hope this clarification gets my patch an approval soon.
  • Tried the above PR42017 patch (which is supposed to release the use of LR as a general register in leaf functions) on CoreMark, using Linaro 4.6, and was surprised to find that despite many reductions in spill code and epilogue (now more often directly return by ldmfd), the generated code still regresses in performance (!).

  • Continuing above, suspecting something from experience (cough) added -falign-functions=8 to the CoreMark compile options. Finally produced a small improvement, while causing a regression for the without-PR42017-patch case (victory?).

  • Worked on PR48808, PR48792 over the weekend, which are cases where paradoxical subregs caused ICE in reload. Posted an ARM backend patch upstream, though now mostly taken over by Richard Sandiford :)

This week

  • Some other PRs, ideas, still work in progress.
  • Started using the porter boards, will try to get 689887 over with this week.

Dave Gilbert

String routines

  • Finally finished the ltrace analysis of the whole of SPEC 2k6 and have written it up - I'll proof read it next week and then send it out to the benchmark list.
  • Ran memset and memcpy benchmarks of larger than cache sizes on A9
    • memcpy on larger than cache sizes (or probably mainly cache miss data) does come back to Neon winning over ARM; my suspicion is that with cache hits we run out of bandwidth on Neon, but that doesn't happen in the cache miss case; why it's faster in that case I'm not sure yet.
    • memset is still not faster for Neon even on large sizes where the destination isn't in the cache.


  • Started looking at 64 bit atomics
  • Looking at the pot of QEmu work with Peter.

Ira Rosen

  • PR 49087 - fixed
  • PR 49038 - opened by Richard - fixed on 4.7, to be backported to 4.5 and 4.6
  • working on widening multiplication for unsigned types and constants (the signed case works fine)

Ken Werner

  • the overhead of the ARM specific unwind tables for some binaries:

  • sometimes the size of the .text section differs which worries me a bit (not necessarily a GCC issue, could be related to the build system)
  • tested a couple of linaro-android images on my panda board
    • ran into a l-i-t issue (now fixed) and discussed with asac and friends
    • and finally got the network up and running :)

  • some 11.11 cycle planning (libunwind work items, "in distributions" spec)

Marcin Juszkiewicz

Michael Hope

Mounir Bsaibes

Peter Maydell

Current Milestones:




complete 1111 planning

2011-05-28 | 2011-05-28





Historical Milestones:

finish qemu-cont-integration



handed off

first qemu-linaro release




qemu-linaro 2011-03




qemu-linaro 2011-04




qemu-linaro 2011-05




close out 1105 blueprints





  • Completed planning work for 1111; all blueprints now created, fleshed out with work items and assigned: [Note that as expected some items under consideration have not made the list; this includes the trustzone work]

  • Some interesting upstream QEMU discussions (list and IRC) on (a) performance improvements [good to see general interest in this] and (b) overhauling the memory API [very long thread but I think the proposed API should be OK for ARM system emulation purposes]
  • 768650: QEMU warnings on recent Linaro OMAP3 kernels: tracked down to the kernel deliberately reading a register it knows doesn't exist on OMAP2/3. Sent a query via Arnd about whether we can get this changed.

  • rebased linaro-qemu to current master
  • Sent patchset which starts ARM QEMU moving towards getting rid of the implicit global CPUState pointer
  • sent patch fixing a configure bug causing it to create recursive symlinks
  • sent a patchset which tightens up the compile time TCG value type checking; this would have detected the build-breaking patch I sent earlier this week...
  • sent patch adding support for active-low interrupts to the LAN9118 model; this is needed when it is used in the Overo OMAP3 board model
  • Meetings:
    • toolchain, standup, GSoC student, doughnuts
  • Current qemu patch status is tracked here:

  • Absences:
  • 1-5 August: Linaro sprint 1111
  • (maybe) 15-16 August: QEMU/KVM strand at LinuxCon NA, Vancouver

  • [LinuxCon proper follows on 17-19th]

Ramana Radhakrishnan

Revital Eres

  • Set-up SPEC2006 profile runs on PowerPC with trunk.
  • Looked at SPEC2006's 462.libquantum.
  • PR745743 - compared different versions mentioned in the PR.
  • Wrote a patch to fix another issue related to how SMS handles debug_insn.

Richard Sandiford

Ulrich Weigand

WorkingGroups/ToolChain/ActivityReports/2011-05-27 (last modified 2011-05-31 20:25:02)