linaro-toolchain

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5668 discussions

by Yao Qi

Hi, I am backporint some patches from FSF mainline, which may improve Linaro 4.5 gcc on thumb2 speed. The first one is done by Richard E. "Improve optimization to transform TST into LSLS" http://gcc.gnu.org/ml/gcc-patches/2010-06/msg02518.html After it applied to Linaro 4.5 tree, EEMBC speed number downgrades, while code size is reduced to some extent. The code difference is like this, 6801 ldr r1, [r0, #0] f831 3013 ldrh.w r3, [r1, r3, lsl #1] -f413 6f00 tst.w r3, #2048 ; 0x800 -f43f af41 beq.w cc <t_run_test+0xcc> +0518 lsls r0, r3, #20 +f57f af44 bpl.w cc <t_run_test+0xcc> 4610 mov r0, r2 After reading cortex-a8 TRM, I can't find exact timing cycles of lsls. Under Chung-Lin's help, we feel that lsls should be slower than tst, but don't have any evidence to prove. If any people is familiar with arm microarch, help is welcome. If our assumption is correct, we may can change this patch to an optimization specific to size only. The second patch is Bernd's "Fix an if statement in arm_rtx_costs_1" http://gcc.gnu.org/ml/gcc-patches/2010-07/msg02096.html After this patch applied, EEMBC benchmark number is not changed. Shall we merge this patch to linaro 4.5 tree? I am inclined to merge it, but if you have concerns on this patch, let us discuss here. -- Yao Qi CodeSourcery yao(a)codesourcery.com (650) 331-3385 x739

15 years, 2 months

Problems with BeagleBoard installation

by Ira Rosen

Hi, I am trying to install my new BeagleBoard xM. I started with https://wiki.linaro.org/Releases/DailyBuilds, but it failed to write to the SD card giving some errors about QEMU (I can try that again if the error messages are important). Dave Martin also gave me this link https://wiki.linaro.org/Source/ImageInstallation, but it doesn't exist anymore. So, I tried these instructions: https://wiki.linaro.org/Source/VexpressImageInstallation with http://snapshots.linaro.org/10.11-daily/linaro-headless/20101107/0/images/t… http://jameswestby.net:8080/view/Hardware%20Packs/job/linaro-omap3%20hwpack… --dev beagle). The installation of the SD card went ok, but the board doesn't work. During boot I see the printings as in the attached file and it doesn't go any further. I hope someone can help me with that, because otherwise I am at dead end... Thanks, Ira

15 years, 2 months

Changing meetings

by Michael Hope

Hi there. I plan to change the Toolchain WG meetings due to daylight savings and to better cover the US. The Monday meeting will be at 0900 UTC which is 9 am in the UK, 10 am in central Europe, and 5 pm in Beijing. The standup calls will be merged into one at 1800 UTC on Wednesday which is 6 pm in the UK, 7 pm in central Europe, and 1 pm on the US East Coast. I don't expect China to call in as it's a quite unreasonable time. I'll update the invites and wiki page to reflect this. We'll start the new times next week, so Monday the 8th will be the first meeting at the new time. -- Michael

15 years, 2 months

Links

by Michael Hope

This is more for the people in the sprint... http://ex.seabright.co.nz/helpers/blueprints#toolchain http://ex.seabright.co.nz/helpers/planner -- Michael

15 years, 3 months

Report of thumb2 tuning investigation

by Yao Qi

The gaol and plan of investigation has been described in [1] In the plan, this task is divided into three parts, 1) patch backport, 2) regression fix, and 3) exploration and study other ARM compilers. This report follow the same manner. 1. Patch backport. 8 patches are listed in [1]. Backport them to Linaro 4.5 tree will improve speed performance. Action/Recommendation: Backport them if speed improves. These patches are ones that I think they *should* improve speed, but "performance surprise" is not impossible. 2. Regression fix. So far (until r99399), Linaro GCC 4.5 is slower than FSF GCC 4.5.0 on some EEMBC benchmarks. Performance regression is introduced by four commits, r99324,r99330,r99369,r99380, see details in [2]. Action/Recommendation: Figure out why speed regression is introduced, and try to fix it. One cent here is that how to avoid speed regression. I do believe that sometimes regression is unavoidable, but it is better if can track them, and keep them manageable. 3. Exploration and study other ARM compilers. In this part, I don't find any possible thumb-2 specific improvements. However, loop optimization and instruction scheduling should be improved on ARM. (This statement may be true to all ports, or even all compilers) Some tickets are opened for this part, LP:660644 Missed optimization opportunities LP:662692 Inner loop in autcor00 can be optimized better LP:656957 LP:645267 Improve code generation on switch statement LP:663793 Tune Swing Modulo Scheduling or Selective Scheduling for ARM LP:656373 Try -fsched-pressure for ARM I have to admit that instruction scheduling is quite hard, but if we can do something here, that will be great. I've put it in "performance-insdie-gcc" session on UDS. Let us talk about it a little there next week. During this investigation, I also find LTO or "whole-program optimization" is useful to some EEMBC benchmarks. (I didn't run LTO/WPO at all, but I got this when read source of benchmarks) [1] Plan of CS304: Thumb2 tuning investigation. http://lists.linaro.org/pipermail/linaro-toolchain/2010-October/000300.html [2] https://wiki.linaro.org/YaoQi/Sandbox/Thumb2SpeedOptimization -- Yao Qi CodeSourcery yao(a)codesourcery.com (650) 331-3385 x739

15 years, 3 months

finding in 4.5.2 20101003 (Linaro) [release 4.5-2010.10-0]

by leonid.moiseichuk＠nokia.com

Hello, Sorry I cannot find a bugzilla. One issue detected during compilation of ffmpeg, it looks like gcc -DHAVE_AV_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -I. -I"/home/ldm/misc/tc/suite/cases/ffmpeg/ffmpeg" -O3 -D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112 -std=c99 -fomit-frame-pointer -Wdeclaration-after-statement -Wall -Wno-switch -Wdisabled-optimization -Wpointer-arith -Wredundant-decls -Wno-pointer-sign -Wcast-qual -Wwrite-strings -Wtype-limits -Wundef -fno-math-errno -fno-signed-zeros -c -o libavcodec/dsputil.o libavcodec/dsputil.c /tmp/ccK6jdSP.s: Assembler messages: /tmp/ccK6jdSP.s:34764: Error: VFP/Neon double precision register expected -- `vmovl.s16 q3,s12' /tmp/ccK6jdSP.s:34781: Error: VFP/Neon double precision register expected -- `vmovl.s16 q2,s8' /tmp/ccK6jdSP.s:34798: Error: VFP/Neon double precision register expected -- `vmovl.s16 q1,s4' /tmp/ccK6jdSP.s:34800: Error: VFP/Neon double precision register expected -- `vmovl.s16 q0,s0' /tmp/ccK6jdSP.s:34820: Error: VFP/Neon double precision register expected -- `vmovl.s16 q8,s8' The sources, assembler and test case are attached. With best wishes, Leonid

15 years, 3 months

2010-10-18 Toolchain WG minutes

by Michael Hope

Minutes from the 2010-10-18 call are here: https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-10-18 I'm afraid I lost the recording of this call so the minutes are incomplete Minutes from the 2010-10-20 standup call are here: https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-10-18 The calls focused on the upcoming summit. -- Michael

15 years, 3 months

Linaro@UDS sessions

by Michael Hope

Hi there. I've updated the list of potential Summit sessions based on yesterdays call. Could people please check the Sessions table on https://wiki.linaro.org/WorkingGroups/ToolChain/Meetings/2010-10-18 and flesh out the agenda for sessions that have your name against them. The agenda should be five to ten discussion points, preferably of things that are not well understood and could use input from the group. There's a good discussion on what to expect at a Summit here: http://oubiwann.blogspot.com/2010/10/q-the-ubuntu-developer-summits.html You can check the already-approved sessions here: http://summit.ubuntu.com/uds-n/ Feel free to join in to any other sessions you might find interesting. There will be quite a few people with diverse backgrounds there, including ~80 people from Linaro, ~400 from Ubuntu, ~200 from the community, and ~200 remote. The overlap between Toolchain and Ubuntu interests might not be great, so I'll make sure a common work room is available for idle time. -- Michael

15 years, 3 months

Flavoured toolchains anyone?

by Marcin Juszkiewicz

Some of Linaro developers works with ARM devices older then ARMv7-a architecture. Other people experiments with hard-float ABI. Each of them has to rebuild toolchain for own use and that means playing with components to have them build properly. But it is no more - I made some patches and armel-cross-toolchain-base since 1.53 version + newer source packages for gcc-4.[45]-armel-cross have support for "debian/flavour" file which allows to set some flags related to toolchain build. So far supported things are: - ARM architecture - float ABI - FPU mode - Thumb mode This feature is not merged into regular Ubuntu packages yet as this is work in progress which needs to be cleaned first. http://people.linaro.org/~hrw/armel-cross-toolchain/ has all source packages needed. Regards, -- JID: hrw(a)jabber.org Website: http://marcin.juszkiewicz.com.pl/ LinkedIn: http://www.linkedin.com/in/marcinjuszkiewicz

15 years, 3 months

Flavoured toolchains anyone?

by Marcin Juszkiewicz

15 years, 3 months

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