Continued looking at constant reuse optimizations, as a background task.
I've fiddled with the costs a bit more to remove false positives.
Continued benchmarking different generic tuning ideas. With each test
run taking most of a day this is slow going.
Took Michael's rootfs that is used for all the toolchain testing and
benchmarking, unpacked it, and repacked it so that it is compatible with
"linaro-media-create", then tested that I could use it to run tests on
LAVA successfully. I was hoping to use this for extra benchmarking
bandwidth, but there's a permissions problem in the LAVA website
software that means it's not yet possible to post private results to the
system, so no proprietary benchmarks yet. I can still continue
pipe-cleaning my process, and maybe run some benchmarks without actually
reporting the results (or perhaps posting them somewhere write-only).
Begun work on adding GCC support for 64-bit shifts with NEON. This is
not quite as simple as it ought to be because a) it's inefficient to
move a value to NEON registers just to do a shift, so it needs to detect
where the value is, and b) right shifts are encoded as left shift by a
negative amount, and negative shift amounts are normally considered
undefined behaviour.
RAG :
RED : None
AMBER: Worried about trunk failures with test runs. Number of
testsuite failures after the atomics merge has increased - more below.
.
Task Planned Estimated Actual
Historical
~~~~~~~
Connect 2011.q4
preparation 28/10/2011 28/10/2011
28/10/2011
Linaro Tasks
~~~~~~~~~~~~
Fully Investigate the O3
performance
regressions 31/01/2012
Writeup on the optimizations 31/12/2011
enabled with PGO
==Progress===
* Debugged the LTO failures for some time this week - not much progress.
* The bootstrap failure with trunk turned out to be the same problem
as with the CFG not being updated properly with some of the
shrink-wrap patches from Alan M . This was fixed on trunk later on
Monday.
* Tested atomics fixes but the test results are overall looking ugly .
Need to do some more debugging. Discovered GDB was broken for single
stepping in ARM atomic sequences - Filed bug report
https://bugs.launchpad.net/gdb-linaro/+bug/892008 here.
* Looked into the vmul / vmla issue for a bit - did some experiments.
Need to write these up and follow up .
=== Plans ===
* Commit the vcvt fixed point patch.
* Finish experiments with the vmla stuff and find out more about this.
* Finish debugging the LTO failures with PGO bootstrap.
* Some research into the O3 perf issues.
Absences.
* Dec 19 - 31st Dec - Tentatively booked
== GDB ==
* Ongoing work on support for cross-platform core file generation.
== GCC ==
* Investigated Launchpad bugs:
#889984 binaries: should step across helper functions
#889985 binaries: can't step out of helper functions
#890764 4.6-11.11 seems to misdetect some files as system header and
implicit extern "C"
== Misc ==
* Gave talk on Linaro at the IBM Germany Technical Expert Council
fall meeting.
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
Sent the patch which implements register pressure estimation in SMS to
the gcc mailing list as RFC.
I looked at some of the regressions in libav and intend to continue
with that this week.
== Last week ==
* Caught up on lots of email.
* Looked into the SMS regression that Revital found. Turned out to be
caused by the ARM backend not modelling the VMLA fast accumulator path.
Need to know how the path actually works before modelling it
(the docs aren't clear).
* Continued to look at -fsched-pressure.
Richard
Summary:
* Create crosstool-ng patches and build embedded toolchain on ubuntu-8.04.4.
Details:
* Crosstool-ng patches
* Update old patches according to Michael's comments and revise them
according the guideline.
* Create patches for nls option, newlib and gdb.
* Try to build embedded toolchain on ubuntu-8.04.4. It works after
installing all the dependence libraries.
Plans:
* Upstream the patches.
* Build and test.
Thanks!
-Zhenqiang
Hi there. The 4.6-2011.10 release causes an output miscompare failure
in 175.vpr from SPEC 2000. The fault didn't exist in 2011.09 and has
cleared in 2011.11.
Does this ring a bell with anyone? Andrew, could it be related to
your widening multiplies fix?
-- Michael
Hi,
* rewrote the Android.mk of libunwind to make use of autoreconf and libtool
* finished my work on libunwind
* upgraded my Linaro Android build environment
* debugged Linaro Android build failures (#891753)
* tested backtracing on the Linaro Android 2.3.5 and 2.3.7 branches
* documented debuggerd usage on Android:
https://wiki.linaro.org/Platform/Android/DebugAndroidSystemComponents
* Debugged a linking failure of the android perflab benchmark that Andy
is seeing. Turns out that the GCC is optimizing two consecutive calls to
sinf and cosf (same angle) are optimized by the GCC to one sincosf call.
The libm provided by the benchmark is lacking sincosf. Workaround is to
use -fno-builtin-sinf -fno-builtin-cosf.
Regards
Ken
== 64 bit atomics ==
* Still fighting membase
* Cleaned up a bunch of other issues, but I'm back at an 'expiry'
issue, where the test
stores some data with a fixed expiry time and then waits until after
it should have expired,
and checks it has. Except on ARM it sometimes doesn't expire quickly
enough. I've got
enough debug now to see that the server processes view of time (which
it updates via
an event about every second) is sometimes very behind gettimeofday()'s
view of time - and
have a small test for it. This doesn't seem to happen on x86. The
good part is that it's now
a much smaller test, the bad part is that it fails rarely - somewhere
between 1/1000 and 1/100
depending on its mood.
* Looked at a few other things to see if they might use 64 bit atomics:
- spice's (as in the VNC like protocol) FAQ said it needed 64bit
atomics and didn't work
on 32bit machines due to that; but the source appears to have been
fixed for 32bit.
- Looked at boost lock-free; it does have an implementation using
gcc's __sync primitives,
however for ARM it uses a hand coded set of primitives, those are
missing the 64 bit implementation,
but the contributor of the ARM code said that the boost lock-free
author preferred
not to use the gcc primtives.
== Other ==
* Testing latest libffi rc
- Had most of my varargs for hf fix in (had missed one part of a test)
* 1 day of non-linaro work
I'm on holiday next week.
Dave
(short week, 4 days)
RAG:
Red:
Amber: we still haven't settled on engineering blueprints and schedule
for the KVM work. Proceeding with some obviously necessary bits anyway
Amber: not clear whether we can do virtio-mmio this quarter
Green:
Current Milestones:
|| || Planned || Estimate || Actual ||
||upstream-omap3-cleanup || 2011-11-10 || 2011-11-10 || ||
(still no milestones, see above)
Historical Milestones:
||add-omap3-networking || 2011-10-13 || 2011-10-13 || 2011-10-13 ||
||a15-systemmode-planning || 2011-10-13 || 2011-10-13 || 2011-09-22 ||
||a15-usermode-support || 2011-11-10 || 2011-11-10 || 2011-10-27 ||
== upstream-omap3-cleanup ==
* spent a half day on this to try to get this blueprint tidied away
even if we aren't going to have much time for the later upstreaming
== other ==
* A15/KVM planning
* experimenting with getting an A15 kernel booting on Fast Model
(see https://wiki.linaro.org/LoicMinier/Sandbox/FastModels
and https://wiki.linaro.org/PeterMaydell/A15OnFastModels)
* estimated required work for doing a qemu model of a board for
one of the Landing Teams (ans: 6 man months +)
