The Bazaar team have been working on improving the performance of bzr
on the gcc-linaro tree. Here's how long the steps take on my machine
with the current 2.4 development version:
Update tip before branching:
bzr pull 20.4 s (no revisions)
Make the branch:
bzr branch --hardlink 4.5 optspace 26.8 s
Do some work and commit it:
...change two files
bzr status 1:05
(again) bzr status 1.7 s
bzr commit . 3.6 s
Push the changes up:
bzr push lp:~michaelh1/gcc-linaro/optspace 3:47 ~9 MB (~40 kB/s
which is saturating my uplink)
Later, the merge master pulls the branch down and merges:
bzr branch --no-tree lp:~michaelh1/gcc-linaro/optspace 36 s ~900 k
bzr merge ../optspace 3:26
The bzr status and bzr commit are quite good. I've asked them to look
into bzr merge.
-- Michael
Hi All,
After downloading linaro toolchain by apt-get in ubuntu, I compiled
the uboot for ARM1136 SoC with -march=armv5 option. And it can compile
successfully. Then I let the uboot run on target boards and system
failed due to "undefined instructions". Checked linaro toolchain
options, it is:
#arm-linux-gnueabi-gcc -v
Using built-in specs.
COLLECT_GCC=arm-linux-gnueabi-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabi/4.5.2/lto-wrapper
Target: arm-linux-gnueabi
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.5.2-5ubuntu2~ppa1'
--with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.5 --enable-shared --enable-multiarch
--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/arm-linux-gnueabi/include/c++/4.5.2
--libdir=/usr/lib --enable-nls --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin
--enable-gold --enable-ld=default --with-plugin-ld=ld.gold
--enable-objc-gc --disable-sjlj-exceptions --with-arch=armv7-a
--with-float=softfp --with-fpu=vfpv3-d16 --with-mode=thumb
--disable-werror --enable-checking=release
--program-prefix=arm-linux-gnueabi-
--includedir=/usr/arm-linux-gnueabi/include --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=arm-linux-gnueabi
--with-headers=/usr/arm-linux-gnueabi/include
--with-libs=/usr/arm-linux-gnueabi/lib
Thread model: posix
gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-5ubuntu2~ppa1)
The imporant options are "--with-arch=armv7-a --with-float=softfp
--with-fpu=vfpv3-d16". I just want to ask whether these options stop
arm-linux-gnueabi-gcc to support old arch? If so, according to gcc
documents at http://gcc.gnu.org/install/configure.html,
"
--with-cpu=cpu
--with-cpu-32=cpu
--with-cpu-64=cpu
Specify which cpu variant the compiler should generate code for by
default. cpu will be used as the default value of the -mcpu= switch.
This option is only supported on some targets, including ARM, i386,
M68k, PowerPC, and SPARC. The --with-cpu-32 and --with-cpu-64 options
specify separate default CPUs for 32-bit and 64-bit modes; these
options are only supported for i386, x86-64 and PowerPC.
--with-schedule=cpu
--with-arch=cpu
--with-arch-32=cpu
--with-arch-64=cpu
--with-tune=cpu
--with-tune-32=cpu
--with-tune-64=cpu
--with-abi=abi
--with-fpu=type
--with-float=type
These configure options provide default values for the
-mschedule=, -march=, -mtune=, -mabi=, and -mfpu= options and for
-mhard-float or -msoft-float. As with --with-cpu, which switches will
be accepted and acceptable values of the arguments depend on the
target.
"
There are only default values for later compiling. Users should be
able to swith to other values by setting other options. But why did
arm-linux-gnueabi-gcc still build "undefined instructions" to arm1136
with "arch=armv5"? In fact arm1136 is armv6.
Then i compiled a toolchain for linaro gcc-linaro-4.4-2011.02-0 codes
by myself, the options are simple:
#arm-none-linux-gnueabi-gcc -v
Using built-in specs.
Target: arm-none-linux-gnueabi
Configured with: ../gcc-linaro-4.4-2011.02-0/configure
--target=arm-none-linux-gnueabi
--prefix=/home/vmuser/development/toolchain/build-toolchain/tools
--enable-languages=c,c++ --disable-libgomp
Thread model: posix
gcc version 4.4.5 (Linaro GCC 4.4-2011.02-0)
Then I compiled uboot by this toolchain again, the uboot can work.
Then why can the toolchain compiled by myself support more arch? And
what performance is lost in my compiling?
Thanks
Barry
== GCC ==
Progress:
* Investigated excessive VFP moves . Partially investigating ways forward.
* Polished up my divmodsi4 patch. Discussed it during the call.
Looking for ways to do it properly at the tree level.
* Got Panda board on Friday.
* Off on Wednesday.
* Conversations with Revital and Chung-Lin. Need to sync up with
Andrew next week.
* Found an issue with binutils and Neon and this is now LP:747837
Plans:
* Continue looking at excessive VFP moves.
* Finish working through Thumb2 speed tickets.
* Set up new Panda board.
* Conversation with Andrew sometime this week.
Meetings:
* 1-1s
* Linaro toolchain meeting
Absences:
* April 15 – 26 -> Booked Holiday.
* May 9-14 - LDS Budapest
== GDB ==
* Committed patch to fix single-stepping across bad ARM/Thumb boundary
(bug #667309) to mainline and Linaro GDB.
* Committed patch to fix accessing "fpscr" register to mainline.
* Ongoing work to fix single-stepping over signal handlers (bug #615978).
Posted yet another updated patch to gdb-patches for comments.
* Implemented patch to support NEON registers in core files (bug #615972).
* Investigated failure to disable address space randomization
(bug #616001).
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
Hi,
== pandaboard ==
* noticed that hw perf events are not working on 2.6.38-1001-linaro-omap
* it seems that the omap kernel has not configured its PMU properly
* perf_event_open syscall returns ENODEV
* started discussion with agreen (#744458)
* noticed that natty puts its glibc into a multilib path
* prevents linaro gcc (and upstream) from being built
== libunwind ==
* created a generic and local variant of the extbl parser
* ran the test suite a few times using different unwind methods
* started to look into the test suite failures
* started to fix a couple of the failures on ARM
Regards
Ken
RAG:
Red:
Amber:
Green: the aircon has been fixed; blessed quiet again
Current Milestones:
| Planned | Estimate | Actual |
qemu-linaro 2011-04 | 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 ==
* the board-ram-limits patchset has been expanded significantly to
address upstream suggestions; it now includes a lot of refactoring
of sun4m (sparc) board code to use the new generic max-ram
functionality instead of a sun4m-specific bit of code. Unfortunately
there is still some pushback upstream on the grounds that a simple
max-ram limit doesn't cater for complicated NUMA situations :-(
== merge-correctness-fixes ==
* working on moving implementation of VLD/VST "multiple structures" forms
into qemu helper functions; the current implementation is correct but
can expand to hundreds of TCG ops which is well beyond the maximum
permitted value, so could potentially overrun a TCG buffer
== other ==
* wrote up some technical/engineering input into what we ought to be
doing with qemu next cycle
* review of a patch by Dmitry Eremin-Solenikov adding ARMv4/v4T support
* some review of s390 TCG patches (not because we have a direct interest
in s390 but as part of being a good citizen upstream)
* sent a pull request for some neon patches that had been on the list
a few weeks; hopefully this will help drain the patch pipeline
* meetings: toolchain, standup, pdsw-tools
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) ~17-19 August: QEMU/KVM strand at LinuxCon NA, Vancouver
Hello,
* Submitted merge requests for SMS patch to gcc-linaro and gcc-linaro/4.6.
* Testing SMS patch which extends the current implementation to
consider loops that contain
instructions with REG_INC_NOTE.
* Filed PRs 48336 48380 for recent fails of trunk on ARM.
* Had a chat with Ramana about the DENbench benchmarks, directions and findings.
* Filed PR 745743 in linaro gcc-bugzilla
Thanks,
Revital
Hi,
* continued bringing patches upstream
- auto-detection of vector size - committed
- changing default vector size to 128 - submitted and testing the
final version
- if-conversion improvement - submitted and now testing the final version
* gcc-linaro-4.6
- submitted a merge request for store sink patch (this patch is
already upstream)
Ira
For reference. We know that the NEON intrinsics in GCC have issues.
I came across this page:
http://hilbert-space.de/?p=22
which has a colour to greyscale conversion done using intrinsics.
gcc-linaro-4.5-2011.03-0 does poorly through saving intermediate
values on the stack. The core of the loop is:
.L3:
mov ip, r4
vld3.8 {d16-d18}, [r6]
vstmia r4, {d16-d18}
ldmia ip!, {r0, r1, r2, r3}
mov sl, r9
adds r7, r7, #1
adds r6, r6, #24
stmia sl!, {r0, r1, r2, r3}
fldd d16, [sp, #24]
fldd d18, [sp, #32]
ldmia ip, {r0, r1}
vmull.u8 q8, d16, d19
stmia sl, {r0, r1}
vmlal.u8 q8, d18, d20
fldd d18, [sp, #40]
vmlal.u8 q8, d18, d21
vshrn.i16 d16, q8, #8
vst1.8 {d16}, [r5]
adds r5, r5, #8
cmp r8, r7
bgt .L3
llvm-2.9~svn128540 does much better:
vld3.8 {d20, d21, d22}, [r1]!
add r3, r3, #1
cmp r3, r2
vmull.u8 q12, d21, d16
vmlal.u8 q12, d20, d17
vmlal.u8 q12, d22, d18
vshrn.i16 d19, q12, #8
vst1.8 {d19}, [r0]!
blt .LBB0_1
and may actually be better than the had-written assembler on Nils's
page due to scheduling the loop comparison earlier.
Richard S, were you looking into this?
-- Michael
