[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[RFC PATCH v4 0/7] hw/arm/virt: Introduce cpu topology support
From: |
Yanan Wang |
Subject: |
[RFC PATCH v4 0/7] hw/arm/virt: Introduce cpu topology support |
Date: |
Tue, 22 Jun 2021 17:34:06 +0800 |
Hi,
This is v4 of the series [1] that I posted to introduce support for
generating cpu topology descriptions to guest. Comments are welcome!
Description:
Once the view of an accurate virtual cpu topology is provided to guest,
with a well-designed vCPU pinning to the pCPU we may get a huge benefit,
e.g., the scheduling performance improvement. See Dario Faggioli's
research and the related performance tests in [2] for reference. So here
we go, this patch series introduces cpu topology support for ARM platform.
In this series, instead of quietly enforcing the support for the latest
machine type, a new parameter "expose=on|off" in -smp command line is
introduced to leave QEMU users a choice to decide whether to enable the
feature or not. This will allow the feature to work on different machine
types and also ideally compat with already in-use -smp command lines.
Also we make much stricter requirement for the topology configuration
with "expose=on".
Furthermore, both cpu-map in DT and ACPI PPTT table are introduced to
present cpu topology to the guest. And an ARM-specific -smp parsing
function virt_smp_parse is introduced, which shares the same logic
with smp_parse() when "expose=off" and follow the stricter parsing
rule when "expose=on".
[1]
https://patchwork.kernel.org/project/qemu-devel/cover/20210516102900.28036-1-wangyanan55@huawei.com/
[2]
https://kvmforum2020.sched.com/event/eE1y/virtual-topology-for-virtual-machines-friend-or-foe-dario-faggioli-suse
Test results about exposure of topology:
After applying this patch series, launch an ACPI guest with virt-6.1 on an ARM
server.
1) Enable the support:
With cmdline: -smp 96,sockets=2,cores=48,threads=1,expose=on
or cmdline: -smp 96,maxcpus=96,sockets=2,cores=48,threads=1,expose=on
we get:
Architecture: aarch64
Byte Order: Little Endian
CPU(s): 96
On-line CPU(s) list: 0-95
Thread(s) per core: 1
Core(s) per socket: 48
Socket(s): 2
NUMA node(s): 1
Vendor ID: 0x48
Model: 0
Stepping: 0x1
BogoMIPS: 200.00
NUMA node0 CPU(s): 0-95
2) Disable the support:
With cmdline: -smp 96
or cmdline: -smp 96,expose=off
we get:
Architecture: aarch64
Byte Order: Little Endian
CPU(s): 96
On-line CPU(s) list: 0-95
Thread(s) per core: 1
Core(s) per socket: 96
Socket(s): 1
NUMA node(s): 1
Vendor ID: 0x48
Model: 0
Stepping: 0x1
BogoMIPS: 200.00
NUMA node0 CPU(s): 0-95
---
Changelogs:
v3->v4:
- add new -smp parameter "expose=on|off" for users to enable/disable the feature
- add stricter -smp cmdline parsing rules on "expose=on" case
- move build_pptt to generic aml-build.c
- add default cluster node in the cpu-map
- rebase on top of latest upstream master
- v3:
https://patchwork.kernel.org/project/qemu-devel/cover/20210516102900.28036-1-wangyanan55@huawei.com/
v2->v3:
- address comments from David, Philippe, and Andrew. Thanks!
- split some change into separate commits for ease of review
- adjust parsing rules of virt_smp_parse to be more strict
(after discussion with Andrew)
- adjust author credit for the patches
- v2:
https://patchwork.kernel.org/project/qemu-devel/cover/20210413080745.33004-1-wangyanan55@huawei.com/
v1->v2:
- Address Andrew Jones's comments
- Address Michael S. Tsirkin's comments
- v1:
https://patchwork.kernel.org/project/qemu-devel/cover/20210225085627.2263-1-fangying1@huawei.com/
---
Andrew Jones (2):
hw/arm/virt: Add cpu-map to device tree
hw/acpi/aml-build: Generate PPTT table
Yanan Wang (5):
vl: Add expose=on|off option support in -smp command line
hw/arm/virt: Add separate -smp parsing function for ARM machines
machine: disallow -smp expose=on for non-ARM machines
device_tree: Add qemu_fdt_add_path
hw/acpi/aml-build: Add Processor hierarchy node structure
hw/acpi/aml-build.c | 75 +++++++++++++++
hw/arm/virt-acpi-build.c | 8 +-
hw/arm/virt.c | 171 +++++++++++++++++++++++++++++++++--
hw/core/machine.c | 7 ++
hw/i386/pc.c | 7 ++
include/hw/acpi/aml-build.h | 7 ++
include/hw/boards.h | 1 +
include/sysemu/device_tree.h | 1 +
qemu-options.hx | 24 +++--
softmmu/device_tree.c | 44 ++++++++-
softmmu/vl.c | 3 +
11 files changed, 326 insertions(+), 22 deletions(-)
--
2.23.0
- [RFC PATCH v4 0/7] hw/arm/virt: Introduce cpu topology support,
Yanan Wang <=
- [RFC PATCH v4 7/7] hw/acpi/aml-build: Generate PPTT table, Yanan Wang, 2021/06/22
- [RFC PATCH v4 2/7] hw/arm/virt: Add separate -smp parsing function for ARM machines, Yanan Wang, 2021/06/22
- [RFC PATCH v4 3/7] machine: disallow -smp expose=on for non-ARM machines, Yanan Wang, 2021/06/22
- [RFC PATCH v4 1/7] vl: Add expose=on|off option support in -smp command line, Yanan Wang, 2021/06/22
- [RFC PATCH v4 6/7] hw/acpi/aml-build: Add Processor hierarchy node structure, Yanan Wang, 2021/06/22
- [RFC PATCH v4 4/7] device_tree: Add qemu_fdt_add_path, Yanan Wang, 2021/06/22
- [RFC PATCH v4 5/7] hw/arm/virt: Add cpu-map to device tree, Yanan Wang, 2021/06/22
- Re: [RFC PATCH v4 0/7] hw/arm/virt: Introduce cpu topology support, Daniel P . Berrangé, 2021/06/22