From: "wangyanan (Y)" <wangyanan55@huawei.com>
To: Paolo Bonzini <pbonzini@redhat.com>, <qemu-devel@nongnu.org>,
<qemu-arm@nongnu.org>
Cc: Barry Song <song.bao.hua@hisilicon.com>,
Peter Maydell <peter.maydell@linaro.org>,
Andrew Jones <drjones@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
Shannon Zhao <shannon.zhaosl@gmail.com>,
wanghaibin.wang@huawei.com, yuzenghui@huawei.com,
Igor Mammedov <imammedo@redhat.com>,
zhukeqian1@huawei.com, Jiajie Li <lijiajie11@huawei.com>
Subject: Re: [RFC PATCH 0/6] Introduce cluster cpu topology support
Date: Thu, 1 Apr 2021 16:43:05 +0800 [thread overview]
Message-ID: <1cddde6a-3338-70f0-1d4c-d6fd5d634bb3@huawei.com> (raw)
In-Reply-To: <20162bd1-b31e-e180-8792-81934e0d005b@redhat.com>
Hi Paolo,
On 2021/3/31 18:00, Paolo Bonzini wrote:
> On 31/03/21 11:53, Yanan Wang wrote:
>> A cluster means a group of cores that share some resources (e.g. cache)
>> among them under the LLC. For example, ARM64 server chip Kunpeng 920 has
>> 6 or 8 clusters in each NUMA, and each cluster has 4 cores. All clusters
>> share L3 cache data while cores within each cluster share the L2 cache.
>
> Is this different from what we already have with "-smp dies"?
As far as I know, yes. I think they are two architecture concepts of
different levels.
A cpu socket/package can consist of multiple dies, and each die can
consist of
multiple clusters, which means dies are parent for clusters. And this
kind of cpu
hierarchy structure is normal in ARM64 platform.
Still take above ARM64 server chip Kunpeng 920 as an example, there
totally are
2 sockets, 2 dies in each socket, 6 or 8 clusters in each die, and 4
cores in each
cluster. Since it also supports NUMA architecture, then each NUMA actually
represents one die.
Although there is already "-smp dies=*" command line parameter for PC
Machines,
a cluster level can be added for x86 architecture if meaningful and
there will be more
work to do in qemu to make use of it. And I am sure that ARM needs this
level.
If there is something wrong above, please correct me, thanks!
Thanks,
Yanan
>
> Paolo
>
> .
next prev parent reply other threads:[~2021-04-01 8:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 9:53 [RFC PATCH 0/6] Introduce cluster cpu topology support Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 1/6] vl.c: Add arch-neutral -smp, clusters=* command line support Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 2/6] hw/core/machine: Parse cluster cpu topology in smp_parse() Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 3/6] hw/arm/virt: Parse cluster cpu topology for ARM machines Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 4/6] hw/i386/pc: Parse cluster cpu topology for PC machines Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 5/6] hw/arm/virt-acpi-build: Add cluster level for ARM PPTT table Yanan Wang
2021-03-31 9:53 ` [RFC PATCH 6/6] hw/arm/virt: Add cluster level for ARM device tree Yanan Wang
2021-03-31 10:00 ` [RFC PATCH 0/6] Introduce cluster cpu topology support Paolo Bonzini
2021-04-01 8:43 ` wangyanan (Y) [this message]
2021-04-27 9:57 ` Philippe Mathieu-Daudé
2021-04-27 11:00 ` wangyanan (Y)
2021-04-27 12:08 ` Philippe Mathieu-Daudé
2021-04-27 12:34 ` wangyanan (Y)
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