== This week ==
* Reviewed patches for the release.
* ...then broke the release. Tried to spin a new one.
* Worked on a "real" fix for bug 850099. Now in testing.
* Looked more at auto-inc-dec stuff. Saw a case that didn't behave
as I expected on the A9. The A9 TRM doesn't describe what happens
for post-indexed addressing, so I asked Ramana. Apparently the
behaviour is expected. Once I have more info, I'll try to update
the patches.
* Worked on neon-highlow-extract and neon-strided-load-extract.
Posted the three patches upstream. Nicely, the one I thought
was going to be the most controversial actually got positive
feedback from Paolo (who wrote the affected code).
Richard
== GDB ==
* Completed hardware watchpoint support for gdbserver.
* Tracked down watchpoint resource accounting regression
on GDB mainline (not present in 7.3).
* Created and published Linaro GDB 7.3-2011.09 release.
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
* Running SPEC2K on the Snowball board. A fresh kernel with HIGHMEM enabled
made it possible to run the tests. Great variations in the results indicates
that something strange is going on. Turning off one of the CPU:s gives
stable result (but slow), so my current guess is that the variations are
caused by a known bug that makes one cpu run slower.
http://igloocommunity.org/bugzilla3/show_bug.cgi?id=1
The patch for this bug was not included in my kernel. Will have another go
with a kernel where the patch is included, as a background activity.
* Planned and started working on the "Adding browsing benchmarks to our
current set of tests"-activity. I will try to keep documentation up to date
here:
https://wiki.linaro.org/AsaSandahl/Sandbox/BrowsingBenchmarks
Experimenting with building Firefox in different ways, so far for x86.
Best Regards
Åsa
(bouncing to linaro-dev as it's generally interesting)
On Fri, Sep 16, 2011 at 8:17 AM, Ramana Radhakrishnan
<ramana.radhakrishnan(a)linaro.org> wrote:
> Hi,
>
> I've been looking at some of the perf regressions we've been seeing
> these days in an attempt to understand what's going on in these cases.
> While I can use perf and get more statistics and do other things to
> figure out why there are perf regressions between 2 binaries along
> with perf record and report, I wonder if it is possible to use u-boot
> to accurately measure what's going on. I would like to try and get the
> values of the performance counters between 2 program points .
>
> I am aware that there are patches that are floating around that allow
> users to set and reset the PMU counters by allowing user level access
> to it in the kernel : while that maybe useful to some I'm not sure if
> I want to take a chance with some other process getting scheduled that
> ends up getting scheduled. Even if there are parts of the kernel that
> save and restore PMU counters associated per process with across
> context switches . I'm looking for as accurate measurements as
> possible in this case and I wonder if u-boot is the best bet for this
> ( in the absence of any dedicated hardware debug / trace unit) given
> not all of us have one.
>
>
> At the minimum to do this I believe we require u-boot or some start-up code to:
>
> * Turn on i-cache and d-cache. ( The current u-boot for panda that I
> get from the linaro-uboot git repo
> git://git.linaro.org/boot/u-boot-linaro-stable.git says "Warning
> Caches turned off" when starting up ). Googling around I find a few
> patches floating around that turn on the d-cache in August from Aneesh
> at TI . We should consider getting these in at some point.
>
> * Looking in $(UBOOT_TOP)/examples/api I see that there are simple
> printf routines and simple stand-alone applications that exist which
> could be used for this purpose. The one problem with this is the fact
> that u-boot appears to require use of -ffixed-r8 for it's purposes
> which *might* mean we need these if we were to use API calls into
> standard u-boot functions .
I wonder if R8 is used in the current ARM version? There's no reason
we can't cherry pick parts such as the serial I/O out into a library
and make the app completely self contained. Skip all of the
initialisation stuff and assume the boot loader has done it for you.
> * Turn on / off speculative prefetching - I believe the kernel does
> this already for a few boards, but could this be done in u-boot just
> before it launches a test application ?
>
> * Turn on the VFP and Neon units.
>
> * Turn on unaligned access so that unaligned accesses are allowed in
> the test applications. GCC will now move towards generating unaligned
> accesses on versions of the architecture that support it, the patches
> upstream have now been approved.
>
> * Memory map / linker scripts to make sure we are putting things in
> the right places (sigh, has to be per-board).
But everything goes in RAM so you have one generic linker script and a
per board MEMORY definition. Similar to:
http://bazaar.launchpad.net/~stm32f-dev/stm32f-dev/stm32f-startup/view/head…
...but even lighter.
> We then write a set of library functions that could then look at what
> performance counters are of interest to us and track them by resetting
> them to 0 and making sure they haven't overflown.
>
> Has anyone else in the group played with u-boot before or has any
> thoughts in this direction ? I am not suggesting that we do this work
> right now but it sounds like an interesting thought of where we can
> get to with this.
My worry is that we miss turning on a feature and get results that
aren't representative. That should be easy enough to check by
baselineing against a Linux hosted run.
We can use NFS or kermit to load the programs. u-boot has a network
console which is nice when you don't have serial. This combined with
an expect script (or LAVA? Paul?) should automate the whole process.
-- Michael
Hi,
* put the sources of the libunwind android port, the patches for
debuggerd and the Android test app online
* documented things at:
https://wiki.linaro.org/WorkingGroups/ToolChain/Outputs/LibunwindDebuggerd
* noticed differences between the old (debuggerd) and the new
(debuggerd+libunwind) backtraces
* I'm still not sure what's going on (maybe they are adding offsets
or something)
* however, the backtrace that libunwind does looks sane to me
Note: I'll be on vacation till October 7th.
Regards
Ken
Hi,
* testing widen-shifts patch on ARM
* SLP improvements:
- submitted a patch to allow not simple ivs in SLP
- committed a patch to allow read-after-read dependencies in SLP
Ira
The Linaro Toolchain Working Group is pleased to announce the release
of Linaro QEMU 2011.09.
Linaro QEMU 2011.09 is the latest monthly release of
qemu-linaro. Based off upstream (trunk) QEMU, it includes a
number of ARM-focused bug fixes and enhancements.
New in this month's release:
- linux-user mode now supports the 64 bit cmpxchg kernel helpers
(only needed for applications compiled for ARMv6 or lower)
- PL111 display controller now supported; this fixes a problem
where BGR was interpreted as RGB on recent versatilepb kernels
Plus a few other minor bug fixes and the usual round of upstream
fixes and improvements.
Known issues:
- The beagle and beaglexm models still do not support USB networking;
we intend to fix this for the 2011.10 release
- There may be some problems with running multithreaded programs in
linux-user mode (LP:823902)
The source tarball is available at:
https://launchpad.net/qemu-linaro/+milestone/2011.09
Binary builds of this qemu-linaro release are being prepared and
will be available shortly for users of Ubuntu. Packages will be in
the linaro-maintainers tools ppa:
https://launchpad.net/~linaro-maintainers/+archive/tools/
More information on Linaro QEMU is available at:
https://launchpad.net/qemu-linaro
The Linaro Toolchain Working Group is pleased to announce the release
of Linaro GDB 7.3.
Linaro GDB 7.3 2011.09 is the second release in the 7.3 series. Based
off the latest GDB 7.3, it includes a number of ARM-focused bug fixes
and enhancements.
This release contains:
* Support for hardware breakpoints and watchpoints in gdbserver
The source tarball is available at:
https://launchpad.net/gdb-linaro/+milestone/7.3-2011.09
More information on Linaro GDB is available at:
https://launchpad.net/gdb-linaro
Hi there. The 2011.09 release has been spun and is testing up well.
The 4.5 and 4.6 branches are now open so feel free to commit any
approved patches.
-- Michael
Hi!
When building Android with the Linaro toolchain, I encountered this link
time error when going from gcc 4.4.3 to gcc 4.6.
"arm-eabi-g++: error: unrecognized option '-avoid-version'"
I find several posts about people encountering the same thing for different
programs.
Was this option removed? Anyone know the story behind it?
Regards
Åsa
