From: Sudeep Holla <sudeep.holla@arm.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Atish Patra <atishp@atishpatra.org>,
linux-kernel@vger.kernel.org, Atish Patra <atishp@rivosinc.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Qing Wang <wangqing@vivo.com>,
linux-arm-kernel@lists.infradead.org,
linux-riscv@lists.infradead.org, Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH v2 8/8] arch_topology: Add support to build llc_sibling on DT platforms
Date: Fri, 20 May 2022 15:56:39 +0100 [thread overview]
Message-ID: <20220520145639.xb33e2z5otdu264y@bogus> (raw)
In-Reply-To: <087176fc-1018-b107-06cc-055d7926b500@arm.com>
On Fri, May 20, 2022 at 02:33:46PM +0200, Dietmar Eggemann wrote:
> On 18/05/2022 11:33, Sudeep Holla wrote:
> > ACPI PPTT provides cache identifiers and especially the last level cache
> > identifier is used in obtaining last level cache siblings amongst CPUs.
> >
> > While we have the cpu map representing all the CPUs sharing last level
> > cache in the cacheinfo driver, it is populated quite late in the boot
> > while the information is needed to build scheduler domains quite early.
> >
> > On DT platforms we can use the pointer to the last level cache as the
> > firmware identifier for the last level cache and build the cpumap sharing
> > the last level cache based on the same.
>
> [...]
>
> > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
> > index 58cbe18d825c..d8a36b0e27c9 100644
> > --- a/include/linux/arch_topology.h
> > +++ b/include/linux/arch_topology.h
> > @@ -69,6 +69,7 @@ struct cpu_topology {
> > int cluster_id;
> > int package_id;
> > int llc_id;
> > + void *llc_fw_node;
>
> Would be nicer if you could set llc_id directly to avoid all this
> addition sync `llc_id and llc_fw_node` code. ACPI PPTT has this
> ACPI_PTR_DIFF() macro which IMHO lets it create distinct ids.
>
Indeed, I initially thought so, but they are 64 bit pointers and choosing
one reference is difficult to take some sort of diff while in ACPI it is in
a static table and we could use the reference to the top of the table.
--
Regards,
Sudeep
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next prev parent reply other threads:[~2022-05-20 14:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-18 9:33 [PATCH v2 0/8] arch_topology: Updates to add socket support and fix cluster ids Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 1/8] arch_topology: Don't set cluster identifier as physical package identifier Sudeep Holla
2022-05-20 12:31 ` Dietmar Eggemann
2022-05-20 13:13 ` Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 2/8] arch_topology: Set thread sibling cpumask only within the cluster Sudeep Holla
2022-05-20 12:32 ` Dietmar Eggemann
2022-05-20 13:20 ` Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 3/8] arch_topology: Set cluster identifier in each core/thread from /cpu-map Sudeep Holla
2022-05-19 16:55 ` Ionela Voinescu
2022-05-20 12:33 ` Dietmar Eggemann
2022-05-20 13:54 ` Sudeep Holla
2022-05-20 15:27 ` Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 4/8] arch_topology: Add support for parsing sockets in /cpu-map Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 5/8] arch_topology: Check for non-negative value rather than -1 for IDs validity Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 6/8] arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 7/8] of: base: add support to get the device node for the CPU's last level cache Sudeep Holla
2022-05-18 9:33 ` [PATCH v2 8/8] arch_topology: Add support to build llc_sibling on DT platforms Sudeep Holla
2022-05-19 18:10 ` Rob Herring
2022-05-20 12:59 ` Sudeep Holla
2022-05-20 14:36 ` Rob Herring
2022-05-20 15:06 ` Sudeep Holla
2022-05-20 12:33 ` Dietmar Eggemann
2022-05-20 14:56 ` Sudeep Holla [this message]
2022-05-19 16:32 ` [PATCH v2 0/8] arch_topology: Updates to add socket support and fix cluster ids Ionela Voinescu
2022-05-20 15:33 ` Sudeep Holla
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