Re: [RFC PATCH 0/6] Introduce cluster cpu topology support

[Philippe Mathieu-Daudé]

Hi Yanan,

On 3/31/21 11:53 AM, Yanan Wang wrote:
> Hi,
> This series introduces the cluster cpu topology support, besides now
> existing sockets, cores, and threads.
> 
> 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.
> 
> Also, there are some x86 CPU implementations (e.g. Jacobsville) where L2
> cache is shared among a cluster of cores instead of being exclusive to
> one single core. For example, on Jacobsville there are 6 clusters of 4
> Atom cores, each cluster sharing a separate L2, and 24 cores sharing L3).

> About this series:
> Note that, this series was implemented based on [3] and [4]. Although they
> have not merged into qemu mainline for now, it's still meaning to post this
> series to express the thoughts first. So a RFC is sent and any comments are
> welcomed and appreciated.

At a glance: tests/unit/test-x86-cpuid.c should be adapted to be generic
(but still supporting target-specific sub-tests) and some aarch64 tests
added.

Similarly the ARM PPTT tables tested in tests/qtest/bios-tables-test.c.

Otherwise, the overall series looks good and coherent, but it isn't my
area :)

Regards,

Phil.