From: Atish Patra <atish.patra@wdc.com>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Anup Patel <anup@brainfault.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Dmitriy Cherkasov <dmitriy@oss-tech.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>,
Jeremy Linton <jeremy.linton@arm.com>,
Juri Lelli <juri.lelli@arm.com>,
"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)"
<linux-arm-kernel@lists.infradead.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Palmer Dabbelt <palmer@sifive.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [RFT PATCH v1 0/4] Unify CPU topology across ARM64 & RISC-V
Date: Mon, 10 Dec 2018 16:11:21 -0800 [thread overview]
Message-ID: <dffd0d6e-bebe-ae31-548b-1778d08a3285@wdc.com> (raw)
In-Reply-To: <20181207134509.GA5913@e105550-lin.cambridge.arm.com>
On 12/7/18 5:45 AM, Morten Rasmussen wrote:
> Hi,
>
> On Thu, Nov 29, 2018 at 03:28:16PM -0800, Atish Patra wrote:
>> The cpu-map DT entry in ARM64 can describe the CPU topology in
>> much better way compared to other existing approaches. RISC-V can
>> easily adopt this binding to represent it's own CPU topology.
>> Thus, both cpu-map DT binding and topology parsing code can be
>> moved to a common location so that RISC-V or any other
>> architecture can leverage that.
>>
>> The relevant discussion regarding unifying cpu topology can be
>> found in [1].
>>
>> arch_topology seems to be a perfect place to move the common
>> code. I have not introduced any functional changes in the moved
>> code. The only downside in this approach is that the capacity
>> code will be executed for RISC-V as well. But, it will exit
>> immediately after not able to find the appropriate DT node. If
>> the overhead is considered too much, we can always compile out
>> capacity related functions under a different config for the
>> architectures that do not support them.
>>
>> The patches have been tested for RISC-V and compile tested for
>> ARM64 & x86.
>
> The cpu-map bindings are used for arch/arm too, and so is
> arch_topology.c. In fact, it was introduced to allow code-sharing
> between arm and arm64. Applying patch three breaks arm.
>
> Moving the DT parsing to arch_topology.c we have to unify all three
> architectures. Be aware that arm and arm64 have some differences in how
> they detect cpu capacities. I think we might have to look at the split
> of code between arch/* and arch_topology.c again :-/
>
> Morten
>
Thank you for bringing this up. I will send a new version and make sure
that it works on arm32 as well.
Regards,
Atish
prev parent reply other threads:[~2018-12-11 0:11 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 23:28 [RFT PATCH v1 0/4] Unify CPU topology across ARM64 & RISC-V Atish Patra
2018-11-29 23:28 ` [RFT PATCH v1 1/4] Documentation: DT: arm: add support for sockets defining package boundaries Atish Patra
2018-12-03 16:46 ` Sudeep Holla
2018-12-12 2:18 ` Rob Herring
2018-11-29 23:28 ` [RFT PATCH v1 2/4] dt-binding: cpu-topology: Move cpu-map to a common binding Atish Patra
2018-12-03 16:55 ` Sudeep Holla
2018-12-03 17:23 ` Atish Patra
2018-12-03 17:33 ` Sudeep Holla
2018-12-03 17:40 ` Atish Patra
2018-12-12 2:21 ` Rob Herring
2018-12-12 2:31 ` Rob Herring
2018-12-12 18:23 ` Atish Patra
2018-11-29 23:28 ` [RFT PATCH v1 3/4] cpu-topology: Move cpu topology code to common code Atish Patra
2018-12-03 16:58 ` Will Deacon
2018-12-03 17:12 ` Sudeep Holla
2018-12-04 9:50 ` Juri Lelli
2018-12-03 17:16 ` Sudeep Holla
2018-12-03 17:31 ` Atish Patra
2018-11-29 23:28 ` [RFT PATCH v1 4/4] RISC-V: Parse cpu topology during boot Atish Patra
2018-12-03 16:59 ` Sudeep Holla
2018-12-05 17:53 ` [RFT PATCH v1 0/4] Unify CPU topology across ARM64 & RISC-V Jeffrey Hugo
2018-12-11 0:26 ` Atish Patra
2018-12-07 13:45 ` Morten Rasmussen
2018-12-07 15:04 ` Sudeep Holla
2018-12-11 0:11 ` Atish Patra [this message]
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