All,
During Connect the suggestion was made that each working group should have
its own IRC Channel for discussions and topics relating to the group in
particular (as opposed to #linaro which is 'generic' Linaro conversations).
Therefore I have just set up #linaro-tcwg on Freenode for the Toolchain
Working Group.
This channel is public and open to anyone who wants to talk with the TCWG
group about anything toolchain related.
Thanks,
Matt
--
Matthew Gretton-Dann
Toolchain Working Group, Linaro
== Progress ==
* 4 day week due to bank holiday.
* Merged binutils arm ifunc changes onto stable branch.
* Worked on getting some git mirrors setup for various toolchain deliverables.
* A certain amount of planning and JIRA card work in preparation for
the next iteration.
* Fixed aarch64_be-* and aarch64-elf testsuite issues with AArch64 ifunc patch.
* Investigated glibc malloc and alternatives.
== Issues ==
* None.
== Plan ==
* Submit new AArch64 ifunc patch after testing complete.
* Finish getting git mirrors setup.
* Look at some gdb testsuite failures.
--
Will Newton
Toolchain Working Group, Linaro
[very short week; two days]
Progress:
* misc
** handover from John Rigby: got a QEMU+KVM+AArch64 setup running with
his work-in-progress patchset
** tracked down weird behaviour when ^C'ing qemu on aarch64
to a bug in glibc's getcontext() implementation (it doesn't
clear the PSTATE field and ends up passing a garbage pstate
to the rt_sigreturn syscall)
Plans:
* VIRT-55: talk to Andre about testing; investigate testing migration
using LAVA
* set up a new qemu-linaro tree/branch as our CI/LAVA input [to keep it
separate from our "we release this" tree]
* restart work on upstreaming omap3 patches as part of my generic qemu
maintenance work (will reduce our maintenance burden in the long term)
-- PMM
== Progress ==
* 3.3 Release
- RC2 is out, we'll have an RC3 (critical bug on X86_64/Darwin)
- Adding some docs to the release
* Infrastructure
- Installing Ubuntu on Chromebook, automating bootstrap+test-suite
- Running the test-suite on a BeagleBoard (LLVM 3.2 and 3.3), no
regressions
- Trying to run an LLVM CBuild job
* Buildbots
- Chasing GCC internal failure on self-host bot
- Chasing more MCJIT failures on all bots
== Issues ==
- Upgrading to 13.04 was a big mistake, had to rollback to 12.10 and
re-configure my whole environment
- Office network/power grid is insufficient for the current population,
I'll be working from home from now on
== Plan ==
* Continue with CBuild for LLVM
* Setup continuous build for bootstrap+test-suite
* Automate Phoronix, setup CI
* If CBuild is done, try running benchmarks with LLVM on it
* As hardware become available, set them up as buildbots
We are using the Linaro prebuilt binary 2013.03 toolchain.
We have a program that does a memcpy of 6 bytes and the source and
destination pointers are both 6 byte arrays (through multiple levels of
struct & union etc).
At -O2 we get the memcpy inlined.
The code area in question is:
22840: f8b7 2054 ldrh.w r2, [r7, #84] ; 0x54
22844: f853 1d12 ldr.w r1, [r3, #-18]!
22848: f042 0202 orr.w r2, r2, #2
2284c: 889b ldrh r3, [r3, #4]
2284e: b292 uxth r2, r2
->22850: f8c7 101a str.w r1, [r7, #26]
22854: f8a7 2054 strh.w r2, [r7, #84] ; 0x54
22858: 83fb strh r3, [r7, #30]
2285a: f8da 3000 ldr.w r3, [sl]
And we get an alignment fault at the str.w marked above.
Looking at the types involved and their location in the containing
structures I don't see how the compiler could think that the destination
was word aligned
(I believe it is guaranteed that dest % 8 == 6)
There are no -march -mcpu or -mtune params passed to the compiler. The
code is running in user space on a A15.
Basic question before we look further:
Is the compiler assuming that cp15 SCTLR.A is 0 so that it is free to
generate unaligned loads and stores?
If the answer to the above is "no" we can isolate the code more and
bring it back to the list.
Thanks,
Bill
---------------------------------------
William A. Mills
Chief Technologist, Open Solutions, SDO
Texas Instruments, Inc.
20450 Century Blvd
Germantown MD 20878
240-643-0836
The Linaro Toolchain and Platform Working Groups are pleased to announce
the 2013.05 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 4.8 2013.05
* Linaro GDB 7.6 2013.05
* 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:
* gcc 4.7 is no longer included
* gdb is updated to 7.6
* Linux release file names no longer include a date to make life easier
for scripted downloads
* ISL/CLooG support is enabled in all builds
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/2013.05
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.
Hi,
I have a usecase where linaro toolchain is used to build my executables and
the sysroot is copied and used as glibc for running my embedded system.
Reason for this is, I want to use the same glibc what the application is
compiled against.
I found a bug fix from glibc community which I want to cherry pick and
rebuild the sysroot to include this fix. But, in the README.txt published
with linaro toolchain binary, there are no instructions for rebuilding
sysroot.
Can anyone point me to info on rebuilding sysroot? If formal steps don't
exist, could you point me to the current process being followed by linaro
so that I can observe the build log and attempt to do the same?
Thanks
Bharath
All,
In the Toolchain Working Group Mans has been doing some examination of SPEC
2000 and SPEC 2006 to see what C Library (glibc) routines impact performance
the most, and are worth tuning.
This has come up with two areas we consider worthy of further investigation:
1) malloc performance
2) Floating-point rounding functions.
This email is interested with the first of these.
Analysis of malloc shows large amounts of time is spent in executing
synchronization primitives even when the program under test is single-threaded.
The obvious 'fix' is to remove the synchronization primitives which will
give a performance boost. This is, of course, not safe and will require
reworking malloc's algorithms to be (substantially) synchronization free.
A quick Google suggests that there are better performing algorithms
available (TCMalloc, Lockless, Hoard, &c), and so changing glibc's algorithm
is something well worth investigating.
Currently we see around 4.37% of time being spent in libc for the whole of
SPEC CPU 2006. Around 75% of that is in malloc related functions (so about
3.1% of the total). One benchmark however spends around 20% of its time in
malloc. So overall we are looking at maybe 1% improvement in the SPEC 2006
score, which is not large given the amount of effort I estimate this is
going to require (as we have to convince the community we have made
everyone's life better).
So before we go any further I would like to see what the view of LEG is
about a better malloc. My questions boil down to:
* Is malloc important - or do server applications just implement their own?
* Do you have any benchmarks that stress malloc and would provide us with
some more data points?
But any and all comments on the subject are welcome.
Thanks,
Matt
--
Matthew Gretton-Dann
Toolchain Working Group, Linaro
Greetings,
I'm using the Linaro tool chain with Eclipse (Juno) (under Windows) and
openOCD to write firmware for an STM32F20x based design (using an ST-Link2
debugger).
In general, that all works fairly well.
The part I'm having problems with is debugging (step-in, etc) from Eclipse.
The execution flow seems chaotic when single stepping through C code: it
skips statements, it jumps into the middle of a function, then returns to
the start of a function, it loops over certain statements (while there's no
loop in the code), etc. (It's close to useless).
I have seen this behavior with other IDE's and tool chains when code was
built with optimization turned on.
However, I specify 'no optimization' (-O0) when I build my code.
My questions:
a) Is there some implicit optimization being done in the compiler, even
though I tell it not to do so, which may affect proper debugging?
b) Are other people using Eclipse (Juno) and are they seeing the same
issue? Are there any known ways to fix this chaotic debugger behavior?
Kind regards,
~ Paul Claessen
== Progress ==
* Performed investigation on gdb7.6 test suite failures and untested test
cases.
* Updated JIRA enteries with test suite failures on arm to track progress.
* Wrote an automation script for selection of individual test cases from a
text file.
* Got the gdb.dwarf2 test suite patch reviewed from Matt and Will.
* Day off on Friday.
== Plan ==
* Finish up initial investigation on gdb7.6 test suite results.
* Complete updates of JIRA enteries after investigation on test suite
results in complete.
* Start work on integration of different testing scripts written in past
couple of months.
* Send gdb.dwarf2 test suite patch upstream.
