ARMv8 [FreeBSD WIKI]

This is a planning session of next steps for the ARMv8 port.

The initial bootstrapping of FreeBSD to ARM64 is nearly complete; we need to start planning the next steps towards getting ARMv8 adopted as a Tier1 architecture. The aim of this group is to bring interested parties in the ARM port discuss the steps needed to achieve this goal and identify areas that require work, their priority and how to achieve them.

#	Topic Description
1	Update on AArch64 port
2	CPU Scaling
	* Minimum support for 48 cores
3	Power Management
	* PSCI
	* big.LITTLE
4	Virtualization
	* bhyve
	* Xen
5	Workload Optimization
	* What are the top 5 frameworks
6	Toolchain
	* LLVM
	* LLDB
	* LLD

In order to attend you need register for the developer summit as well as by email for the session and be confirmed by the working group organizer. Follow the guidelines described on the main page or what you received by email. For questions or if in doubt ask andrew.wafaa@arm.com

Please do NOT add yourself here. Your name will appear automatically once you have received the confirmation email. You need to put your name on the general developer summit attendees list though.

Name	Username / Affiliation	Topics of Interest	Notes
AndyWafaa	ARM Ltd.		Session chair
ZbigniewBodek	zbb		Working on ARMv8 port
AndrewTurner	andrew		Working on ARMv8 port
JulienGrall	Citrix (Xen Project)	Virtualization (Xen)
LarryWikelius	Cavium Inc.
GlenBarber	gjb
ArunThomas	BAE Systems
JustinHibbits	jhibbits	Clock & Power Domain
StaceySon	sson	QEMU
BrooksDavis	brooks
DavidChisnall	theraven
EricLeBlan
MichaelBrinke-Engel

Topics

Update on AArch64 port

arm64 Wiki page

FreeBSD Foundation sponsored by ARM & Cavium Work carried out by Andrew Turner & SemiHalf. Work is progressing well but not necessarily as quick as some would like. AArch64 is in HEAD, usable with QEMU and Foundation Model with some limitations. Appears some issues remain with PMAP limiting toolchain. Targeting Tier1 architecture for FreeBSD11

ARM sponsoring University of Cambridge to port Dtrace and HW Performance Counters Initial code in HEAD

zbb demoed FreeBSD running on a Cavium ThunderX platform utilising 48cores.

CPU Scaling

Able to boot with48 cores but stability is an issue Unsure as to where the instability lies
Lack of knowledge/experience with high core counts No fundamental issues expected, just new territory

Power Management

ARM expressed importance of Power Management

PSCI driver is now in HEAD
More details covered in the Clock/Power Domain session from the previous day

Virtualization

bhyve There is a GSOC project to port FreeBSD/buhyve to ARMv7 (32bit). Reason is easy access to hardware, maturity of FreeBSD on ARMv7. Use 32bit as foundation and if possible port to AArch64 during GSOC
Xen Citrix have ported Xen. FreeBSD on AArch64 works as DomU guest only. Dom0 still to be worked on

Workload Optimization

What are the top 5 frameworks? - Standard web stack NGINX is the big ticket item - Language runtimes Erlang is important

Toolchain

LLVM Support is upstream but may not be completely in FreeBSD's implementation. FreeBSD's use is extensive and is catching issues that others have not seen
LLDB Work is ongoing
LLD Work is ongoing. Least developed of the toolchain stack?
GDB jhb volunteers to work on port
OpenMP (LLVM libomp)(Adrian's WIP for libgomp) Deemed important, need someone to look at it

GPU / GPGPU support?

What are the plans for support?

opencl fully support AArch64 ARM is woring on this, not necessarily with FreeBSD in mind

Fault Tolerance / High Availability Key item for XinuOS. No ideas on what HW will implement specific HA methods. Software based HA should be no problem

Application specific offload engines

Some silicon vendors are deploying specific engines. Need to work with vendors to implement support.