linaro-toolchain August 2012

linaro-toolchain@lists.linaro.org

16 participants
36 discussions

by Christophe Lyon

== Progress == * Validation of my vext patch in big-endian mode proved that proper support would be non-trivial. Spent a lot of time writing a self-testing executable test, which works in both big and little endian modes. Posted an updated patch which makes no optimization in big-endian. After discussion with Ramana, I will post a 2nd patch which improves the testing in big-endian mode. * In the process, wrote a patch to fix 3 other testcases which used to fail in big-endian mode. * Received no answer from the original contributor of bswap16 support patch. == Next == * Have my vext patch accepted on trunk. * Continue with bswap16 support.

12 years, 9 months

[ACTIVITY] report week 34

by Peter Maydell

(Short week: 3 days) Current Milestones: || || Planned || Estimate || Actual || || clean up kvm-qemu cp i/f || 2012-09-20 || 2012-09-20 || || || fake-trustzone || 2012-10-15 || 2012-10-15 || || Also planned: general keeping up with kernel changes; upstream patch review; qemu-linaro releases. May change dates to align with overall KVM plan for the quarter when that is finalised. Previous Milestones: ||cp15-rework || 2012-01-06 || 2012-06-23 || 2012-06-24 || ||a15-lpae-support || 2012-07-13 || 2012-07-20 || 2012-07-20 || == clean-up-kvm-patches == * patches as they stand look good; currently blocked waiting for changes to go into kernel side == track-kvm-abi-changes == * thinking about some interesting corner cases in accessing cp15 state via KVM, notably how userspace should get at the cache ID registers, which are exposed by hardware as a "select" and "read value of selected register" cp15 register pair. Consensus seems to be that the kernel should deal with converting this into a simple interface that userspace can use to just read all the ID register state at once. == other == * fixed breakage in ARM TCG host support (recent changes had failed to account for the ABI requirement that 64 bit arguments to functions must be passed in even-odd register pairs) * KVM bootwrapper: pushed 64-bit-addresses-in-dtb patch to main repo; reviewed patch from Guodong Xu adding uInitrd support KVM blueprint progress tracker: http://apus.seabright.co.nz/helpers/backlog?group_by=topic&colour_by=state&… -- PMM

12 years, 10 months

[ANNOUNCE] Linaro Toolchain Binaries 2012.08 released

by Zhenqiang Chen

The Linaro Toolchain Working Group is pleased to announce the 2012.08 release of the Linaro Toolchain Binaries, a pre-built version of Linaro GCC and Linaro GDB that runs on generic Linux or Windows and targets the glibc Linaro Evaluation Build. Uses include: * Cross compiling ARM applications from your laptop * Remote debugging * Build the Linux kernel for your board What's included: * Linaro GCC 4.7 2012.08 * Linaro GDB 7.4 2012.06 * A statically linked gdbserver * A system root * Manuals under share/doc/ The system root contains the basic header files and libraries to link your programs against. Interesting changes include: * Enable threaded gold linker in Linux package The Linux version is supported on Ubuntu 10.04.3 and 12.04, Debian 6.0.2, Fedora 16, openSUSE 12.1, Red Hat Enterprise Linux Workstation 5.7 and later, and should run on any Linux Standard Base 3.0 compatible distribution. Please see the README about running on x86_64 hosts. The Windows version is supported on Windows XP Pro SP3, Windows Vista Business SP2, and Windows 7 Pro SP1. The binaries and build scripts are available from: https://launchpad.net/linaro-toolchain-binaries/trunk/2012.08 Need help? Ask a question on https://ask.linaro.org/ Already on Launchpad? Submit a bug at https://bugs.launchpad.net/linaro-toolchain-binaries On IRC? See us on #linaro on Freenode. Other ways that you can contact us or get involved are listed at https://wiki.linaro.org/GettingInvolved.

12 years, 10 months

[Activity] Week 34

by Zhenqiang Chen

Summary: * Identify the root cause of performance regression for the "split2" patch. * Validate Linaro binary toolchain prerelease. Details: 1. Identify the root cause of performance regression for the "split2" patch. * Code alignment is the root cause for the performance regression (Michael reproduced it with "__attribute__ ((aligned(16)))"). * "build-id" section is the root cause of result difference from cbuild test (the additional section makes the function address different). * Workout a small case to show the impact of code alignment on performance. 2. Linaro binary toolchain 2012.08 prerelease validation. All tests pass. Absence: * Annual leave: Aug. 24. Plans: * Linaro binary toolchain 2012.08 release. * Start shink-wrap work. Best regards! -Zhenqiang

12 years, 10 months

LTO for the kernel

by Christian Robottom Reis

In case nobody here caught it: https://lwn.net/Articles/512548/ Interesting? Worth talking to Andi about it for ARM? -- Christian Robottom Reis | [+55 16] 3376 0125 | http://async.com.br/~kiko Async Open Source | [+55 16] 9112 6430 | http://launchpad.net/~kiko

12 years, 10 months

[ACTIVITY] Aug 21-Aug 24

by Christophe Lyon

== Progress == * Fixed problems with my patch for "constant vec permute operation for the vext instruction" blue-print, validated in cbuild. * Ported it to trunk and submitted for review. R.Earnshaw requested validation on big-endian. I need to upgrade my qemu to have it supported. * Compiled my Neon intrinsics testsuite with LLVM (version 3.2 trunk 160543). It compiles at O0/O1/O2/O3, but only O0 produces the expected results. Errors include: vset_lane, vld3, and vld4. * Started looking a bswap16 support == Next == * Have my "constant vec permute operation for the vext instruction" patch accepted on trunk * Continue with bswap16 support.

12 years, 10 months

[ACTIVITY] 20 August - 24 August

by Matthew Gretton-Dann

== Progress == * Follow up from 2012.08 Toolchain release * Updated Wiki pages * Start working on symbol_ref split benchmarking. * Backport to PR54212 done upstream to 4.6 and 4.7 * Started picking up Hot/Cold partitioning in PGO blueprint: * https://blueprints.launchpad.net/gcc-linaro/+spec/hot-cold-partitioning-in-… * Got SPEC running locally and I think I have reproduced Ramana's failures. == Next Week == * Bank Holiday on Monday * Investiagte SPEC failures in Hot/Cold PGO * Get symbol_ref benchmarking going properly == Future == * Look at Cards for Vectorization, PGO and LTO with Michael. -- Matthew Gretton-Dann Linaro Toolchain Working Group matthew.gretton-dann(a)linaro.org

12 years, 10 months

Testing builds via cbuild

by Michael Hope

(cc'd to linaro-toolchain to archive) Hi Matt. I've had a look at the manual builds you tried to spawn. Here's what I did to run cbuild locally to test it: * cd linaro * bzr branch lp:cbuild * cd cbuild/slaves * cp -a example `hostname` * cd `hostname` * make -f ../../lib/build.mk final/gcc-4.8+svn190558.stamp I'm not proud of the whole 'slaves/$hostname' setup, but it is what it is. Results are in $version, such as gcc-4.8+svn190558. The build tree is in $version/gcc/default/build. Nuke using rm -rf final results $version. See lib/common.mk and override the email address etc in local.mk to stop build results going out You should put a proxy in $http_proxy or ~/.wgetrc to reduce the download cost. Please add to the cbuild README. A nit: we use the Debian versioning scheme so the version should be 4.8~svn190558, i.e. a SVN checkout leading up to 4.8. Compare with 4.7+svn1234, which is a SVN checkout of the 4.7 branch. The tarballs look generally good. I've spawned them into the a9hf queue as that's what we benchmark on. Note that they're low priority due to not having 'linaro' in the name. -- Michael

12 years, 10 months

Function alignment and benchmark results

by Michael Hope

Zhenqiang's been working on the later split 2 patch which causes more constants to be built using a movw/movt instead of a constant pool load. There was an unexpected ~10 % regression in one benchmark which seems to be due to function alignment. I think we've tracked down the reason but not the action. Compared to the baseline, the split2 branch took 113 % of the time to run, i.e. 13 % longer. Adding an explicit 16 byte alignment to the function changed this to 97 % of the time, i.e. 3 % faster. The reason Zhenqiang and I got different results was the build-id. He used the binary build scripts to make the cross compiler, which turn on the build ID, which added an extra 20 bytes ahead of .text, which happened to align the function to 16 bytes. cbuild doesn't use the build-id (although it should) which happened to align the function to an 8 byte boundary. The disassembly is identical so I assume the regression is cache or fast loop related. I'm not sure what to do, so let's talk about this at the next performance call. -- Michael

12 years, 10 months

Actions from Toolchain Performance Call 21 August 2012

by Matthew Gretton-Dann

All, I have updated the minutes from today's Performance Call here: https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2012-08-21 The following are the actions from the meeting: * michaelh to folow-up and ping Mans on getting a hold of his benchmark runs * michaelh to investigate regression with movw/movt patch by hand * mgrettondann to run current symbol ref splitting patch over SPEC against FSF trunk * michaelh to point mgrettondann to existing cards * michaelh and mgrettondann to start writing card for PGO work * mgrettondann to pick up Hot/Cold Partitioning patch from ramana, cross-test against SPEC for correctness, and then do a benchmarking run * ramana to create a Blueprint for min-idion in middle-end and update Todo list with link * mgrettondann to update todo list with changes in 2012.08 release. * zchen to work on shrink-wrapping * clyon to update his vext patch The next meeting is on 4 September and a proposed Agenda is here: https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2012-09-04 Please add any items you wish to discuss to the agenda. Thanks, Matt -- Matthew Gretton-Dann Linaro Toolchain Working Group matthew.gretton-dann(a)linaro.org

12 years, 10 months

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linaro-toolchain August 2012