linaro-toolchain April 2011

linaro-toolchain@lists.linaro.org

29 participants
73 discussions

by Michael Hope

Hi there. A first-pass list of summit sessions is up at: https://wiki.linaro.org/MichaelHope/Sandbox/1111Blueprints The next step is to investigate these areas and come up with a basic plan that can be discussed during the summit. I've put your names against the sessions as follows: Andrew: Broad tuning Dave: String routines everywhere Dave: QEMU topic #2 Doug: STM support Ira: Vectoriser and NEON performance Ken: 64 bit sync primitives Ken: Good backtracing Ken: End-developer tools bluesky Michael: Publish benchmarking of the toolchain Michael: Binary builds Michael: Deeper validation Peter: QEMU bluesky Ramana: Thumb-2 performance brainstorm Ramana: GCC backend rework Ulrich: GDB as a cross-debugger Ira and Dave, I know you won't be at the summit but we'll see about being able to call in. Could you all please have a read of the outline, investigate these topics, and draft up a blueprint-style list of work items to achieve it? Record any notes in the sandbox page[5] or in a child page if needed. Larger topics may warrant a specification[1]. I'd like these done by the end of next week. I'd expect to spend up to a day on the topics you already understand and more on broad topics. For reference, the see the draft TRs[2] and spreadsheet [3]. I've added some GDB topics to the spreadsheet that still need to go onto the wiki page. The outlines should touch each of these TRs in some way so let me know if I've missed anything. There's more good information on the process and style at: https://wiki.linaro.org/Process/Blueprints https://wiki.linaro.org/Process/WorkItemsHowto https://wiki.linaro.org/Resources/FAQ Questions? Need more detail? Let me know. -- Michael [1] https://wiki.linaro.org/Process/SpecTemplate [2] https://wiki.linaro.org/Cycles/1111/TechnicalTopics/Toolchain [3] https://spreadsheets.google.com/ccc?key=0Ap7fWLePADFVdHkxYy1INTZmMEd4bkwxSG… [4] there is no 4... [5] https://wiki.linaro.org/MichaelHope/Sandbox/1111Blueprints

14 years

[ACTIVITY] 18th - 21st April

by Andrew Stubbs

Merged & tested the outstanding merge requests into Linaro GCC. Spin the Linaro GCC 4.5 and 4.6 releases. Uploaded the tarballs to Michael. Submitted a patch upstream that removed some redundant code that had confused me a introduced a bug into my Thumb2 constants patch. http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03756.html This patch is now approved and committed upstream. I'll commit it internally when the rest of my ARM/Thumb constant handling changes are upstream. Worked on addressing RichardE's concerns with my Thumb2 constants patch. Tried to split it into smaller chunks, and rename the constraints. Posted the patches upstream: 1. a small patch upstream to clean up MOWV support. http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03768.html (Now approved and committed.) 2. ADDW and SUBW support. http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03783.html 3. Replicated constants for constant splitting. http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03883.html Committed upstream Dan's Vector shift test cases patch that was approved last week. Pushed the same patch to Linaro GCC 4.6. ---- Upstream patched requiring review: * NEON scheduling patch http://gcc.gnu.org/ml/gcc-patches/2011-02/msg01431.html * ARM EABI half-precision functions (reposted 2011-04-14) http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03210.html * ARM Thumb2 addw/subw support. http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03783.html * ARM Thumb2 Replicated constants http://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg03883.html

14 years

Performance meeting agenda for today.

by Ramana Radhakrishnan

Hi, Agenda for today's performance call . Sorry about the last minute posting and I'll put this in the wiki soon enough. 1. Sync-up on what's been happening around the group: a. Coremark regressions. b. Thumb2 constants patch. c. divmodsi4 and vfp register moves. d. DENBench investigations. 2. Planning for the summit and turning some of the ideas into blueprints. 3. AOB. cheers Ramana

14 years

[ACTIVITY] Apr.18 -- Apr.24

by Chung-Lin Tang

== Last week == * PR48250, rehaul arm_legitimize_reload_address(). Richard Sandiford caught a bug of mine where I overlooked the valid index range of NEON quad-word load/stores. Quickly whipped up a fix, soon approved and committed upstream. * LP #744754, ICE in NEON struct-mode auto-inc-dec MEMs. Pushed upstream patch for a merge to Linaro 4.5. * PR46888, bit-field insert optimization patch. Resumed investigating, mailed Andrew Pinski for more information on that REG_EQUAL note issue he mentioned on gcc-patches; can't quite reproduce it myself. * CoreMark ARMv6/v7 regressions: posted a patch set to gcc-patches. Still waiting review. * Reported to Bernd and AndrewS on an issue (LP #748138) which seems to be related to the shrink-wrap patch. This ICE does not seem to be avoided by doing -fno-shrink-wrap. * A few tasks related to Linaro-Budapest event travel. == This week == * Do the merge of the new combine patches to Linaro, and test. * LP #689887 is still in progress. * Hope to experiment with a few more optimization ideas.

14 years

NEON intrinsics vs. assembly code

by Richard Sandiford

Michael mentioned that some users reported seeing better preformance from RVCT using arm_neon.h then they did when coding directly in assembler. He suggested we try the same thing for GCC. Here's an experiment using the example that Jim Huang posted to the dev list recently: https://wiki.linaro.org/RichardSandiford/Sandbox/IntrinsicsPerformance The summary is that the C version needs to borrow a trick from the assembly code in order to be competitive. If it does that, though, the C code can be faster. I think this is mostly down to scheduling, although I haven't checked in detail yet. Richard

14 years

[ACTIVITY] 2011-04-21

by David Gilbert

== String and Memory routines == * Profiled denbench with perf and produced a set of stats to show which programs spent how much time in libc and how much time was spent in each routine. While some of the benchmarks are good (like aes) and spend almost no time in libc some of the others (MPEG codecs especially) seem to spend significant times in libc. * Ran all of denbench through latrace to generate sets of library calls; post processed them to extract the section between the clock() calls (and hence in the timed portion) and analysed the hot library calls. I've looked at some of the output but not all of it yet; I get output like: Memcpy stats (dst align/src align/length/number of occurrences/total size copied) memcpy: 0,0,1 , 1588520, 1588520 memcpy: 16,28,4096 , 1, 4096 memcpy: 4,20,16384 , 855, 14008320 This shows that for a bunch of tests they do an inordinate number of 1 byte memcpy's, and a few hundred larger memcpy's with an address %32 which is 4 (and destination %32 is 20) - so not aligned but at least equally misaligned. * Started writing up a report on some of the stats * Also started to try and extract the same stuff from SPEC2k6 == QEMU == * Tested Peter's QEmu release earlier in the week (On Lucid so didn't hit his natty bug) * Wrote up a couple of specs (one for TrustZone and the other for Device Tree integration)

14 years

[ACTIVITY] Weekly status

by Revital Eres

Hello, Submitted the following patches to GCC trunk: [1] Avoid unfreed memory when SMS fails (committed to trunk GCC) - http://gcc.gnu.org/ml/gcc-patches/2011-04/msg01204.html [2] Free sccs field (committed to trunk GCC)- http://gcc.gnu.org/ml/gcc-patches/2011-04/msg01205.html [3] New flag to apply SMS when SC equals 1 (committed to trunk GCC) - http://gcc.gnu.org/ml/gcc-patches/2011-04/msg01293.html [4] Avoid considering debug_insn when calculating SCCs - http://gcc.gnu.org/ml/gcc-patches/2011-04/msg01294.html [5] Support instructions with REG_INC_NOTE - http://gcc.gnu.org/ml/gcc-patches/2011-04/msg01309.html Returned looking into DENbench's benchmarks. Thanks, Revital

14 years

[ACTIVITY] Apr 18 - Apr 21

by Ulrich Weigand

== GDB == * Created Linaro GDB 7.2-2011.04-0 release. * Committed patch to fix accessing "fpscr" register to Linaro GDB. * Failure to disable address space randomization (bug #616001) has been fixed in the kernel; closed the Linaro GDB bug. == GCC == * Ongoing analysis of bug #759409 (Profiled bootstrap fails). Identified two independent problems, one related to a new CodeSourcery feature, and one a mis-optimization of final-stage cc1plus which is also present in FSF GCC 4.5 (PR 43085). Ongoing investigation to track down the root cause of the latter problem. == Schedule == * Public holidays 04/22 - 04/25. Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand | Phone: +49-7031/16-3727 STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E. IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht Stuttgart, HRB 243294

14 years

[ACTIVITY] report week 16

by Peter Maydell

RAG: Red: Amber: Green: another monthly qemu-linaro release out on schedule Current Milestones: | Planned | Estimate | Actual | qemu-linaro 2011-04 | 2011-04-21 | 2011-04-21 | 2011-04-21 | Historical Milestones: finish qemu-cont-integration | 2011-01-25 | 2011-01-25 | handed off | first qemu-linaro release | 2011-02-08 | 2011-02-08 | 2011-02-08 | qemu-linaro 2011-03 | 2011-03-08 | 2011-03-08 | 2011-03-08 | == maintain-beagle-models == * qemu-linaro 2011.04 tested and released * had to do another last minute -1 respin to fix a problem caught by ubuntu package builds; we need to come up with a process that lets us do test package builds prior to release so we can fix this sort of issue in a less last-minute fashion == merge-correctness-fixes == * sent patch: fix semihosting SYS_HEAPINFO (seems to have issues though) * sent patch: UNDEFs in Neon load/store space * sent patches: fix build issues on sparc * sent patch: bump the initrd load address to work with bigger kernels * sent patch: set Invalid flag for float-to-int conversion of NaN * sent patch: move vld/vst multiple to helper functions * reviewed patches from Aurelien doing some general softfloat cleanup * sent out a version of my performance counters patch which just does a basic dummy implementation without the cycle counter (since the cycle counter bits were going off down a blind alley rather and this part is the last thing needed to be able to boot Linaro vexpress images on stock upstream QEMU) == other == * trying to nail down proposed QEMU work for next cycle; work-in-progress: https://wiki.linaro.org/PeterMaydell/Qemu1111 * meetings: toolchain, standup Current qemu patch status is tracked here: https://wiki.linaro.org/PeterMaydell/QemuPatchStatus Absences: Holiday: 22 Apr - 2 May 9-13 May: UDS, Budapest (maybe) 15-16 August: QEMU/KVM strand at LinuxCon NA, Vancouver [LinuxCon proper follows on 17-19th]

14 years

[ACTIVITY] weekly status

by Ken Werner

Hi, libunwind: * added initial support for resuming at a certain stack frame * posted unw_resume support plus some some testsuite fixes on the ml * there are still some issues left if signal handlers/frames are involved Note: Friday is a public holiday. Regards Ken

14 years

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linaro-toolchain April 2011