[VIRT-198 # QEMU: SVE Emulation Support ]
Last of the patches merged to mainline. Epic is now closed.
[VIRT-282 # QEMU: Accelerate TCG with KVM ]
A hallway talk with Paolo lead to a write-up, and Alex encouraged me to create
the epic. The epic description contains a link to the write-up, if anyone is
interested. I'd like to at least create a vm, measure some round-trip costs,
and properly gauge the level of difficulty. Beyond that... we'll see.
[Upstream]
Patch review:
- risc-v decodetree patches v2.
Produced some patches against decodetree itself in response.
I'm hopeful to see a much cleaner v3.
- per-cpu locks
[KVM Forum]
- Unsurprisingly, lots of people worked on speculation mitigation this year.
- Lots of focus on "ram", and the allocation and management thereof.
- Four talks on improving nested virtualization.
- The rest to follow in the trip report.
r~
== Progress ==
* FDPIC
- Posted binutils and uClibc-ng patches to fix cortex-M support, under
discussion
- GCC: handling feedback on v3 patches.
Experimented thumb-1 builds, failed.
* GCC upstream validation:
- reported a few regressions
- dealing with some random results, again
* GCC:
- bug report on aarch64 about misaligned accesses. Waiting for more
details to reproduce the problem.
* misc (conf-calls, meetings, emails, ....)
- Working on fixes of our benchmarking harness to support new gcc-8 releases.
== Next ==
FDPIC:
- GCC: followup v3 patches
- uclibc-ng: look at how to test fdpic mode with openadk
- use qemu-system mode to run more tests
Benchmarking:
- fix harness until they support gcc-8
== This Week ==
* GNU-405: Implement division using vrecpe / vrecps (4/10)
- Patch validated and posted upstream.
* SVE ACLE intrinsics (4/10)
- Going thru documentation.
* GNU-235: Provide value-range info for erf family of functions (1/10)
- Working on patch.
* Misc (1/10)
- Meetings
== Next Week ==
- Continue GNU-235, SVE ACLE intrinsics
Upstream Work ([VIRT-109])
==========================
- started looking at {Qemu-arm} {RFC v4 00/71} per-CPU locks
Message-Id: <20181025151103.GA19931@flamenco>
- this is a precursor to Emilio's {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
Other Tasks
===========
- Attended KVM Forum 2018
- I am now Spectre'd out ;-)
- Some interesting discussions on upstream CI
- will save the rest of my notes for the conference report
- Delivered QEMU Keynote/Status report @ KVM Forum 2018
- Here are [the slides]
[the slides]
http://people.linaro.org/~alex.bennee/org/presentations/kvm18-qemu-keynote.…
Current Review Queue
====================
* {Qemu-arm} {RFC v4 00/71} per-CPU locks
Message-Id: <20181025151103.GA19931@flamenco>
* {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
* {PATCH v2 0/3} Modern shell scripting (use $() instead of ``)
Message-Id: <20181018031723.23459-1-maozhongyi(a)cmss.chinamobile.com>
* {PATCH 0/7} Acceptance Tests: basic architecture support
Message-Id: <20181004151429.7232-1-crosa(a)redhat.com>
* {PATCH v7 00/19} Fixing record/replay and adding reverse debugging
Message-Id: <20181010133333.24538.53169.stgit@pasha-VirtualBox>
* {PATCH v2 0/3} Bootstrap Python venv and acceptance/functional tests
Message-Id: <20181009041826.19462-1-crosa(a)redhat.com>
--
Alex Bennée
[LLVM-203] Investigation into profiling and code-size optimizations
- Collected the remaining data I needed over the weekend.
- Wrote up report
- Rebased patches on tip of trunk
- Attached results and report to Jira issue.
- A one line summary of the results is that if you are lucky you can
get close to peak performance at close to Os code size if your program
happens to spend most of its time in a few small places. If you are
unlucky then increased inlining and unrolling can still result in an
overall code size increase over -O3 but the effect will be limited.
[LLVM-158] Monitor and maintain buildbots
- Relatively quiet week, a couple of patches pinged for fixes/reverts.
== This Week ==
* TCWG-1234: Coremark regression (7/10)
- Fixed golang regressions with the patch.
- Posted patch upstream to change hoisting order and apply cost model.
* Public holiday (2/10)
* Misc (1/10)
- Meetings
== Next Week ==
- TCWG-319, SVE
[VIRT-214 # SVE System Registers ]
v4 posted and merged to target-arm.next; will be in master shortly.
That will complete basic SVE system mode support.
[UPSTREAM]
tcg-next patches collected and flushed.
Dug into apparently excessive overhead in aarch64 guest tlb flushing, noticed
by chance while doing something else. Two patches upstream, several more
written but need cleanup. Total overhead down from 25% to 9%.
r~
=== Work done during this past week ===
* GNU-296 / GCC PR85434 / CVE-2018-12886:
+ few more issues fixed and associated testing
+ now also running Thumb-1 bootstrap and testing
* Prepare patch to further update cpus and architectures in bfd
* Line management
=== Plan for week 43 ===
* GNU-296 / GCC PR85434 / CVE-2018-12886:
+ finish testing, and submit new stack protector patch for upstream review
* LLVM-432 (Support arithmetic on FileCheck regex variable):
+ extend testcase coverage (add tests for latest syntax change and
add more negative testing)
+ finish cleaning up the code
* Try to reproduce perf issue mentioned in week #30's weekly report on
latest perf
* Line management
Progress:
* VIRT-65 [QEMU upstream maintainership]
- code review
- use ID registers as master source for "should this CPU
have this feature" information (rth)
- clean up 32-bit Neon to use vector infrastructure (rth)
- don't let the kernel get loaded on top of our builtin
bootloader if it happens to ask for a zero text offset
- Xilinx Versal board patches
- target-arm pull requests
- some minor patches to fix new clang warnings
- preparation for KVM Forum/QEMU Summit etc next week
thanks
-- PMM
