Date:   Mon, 27 Feb 2023 12:55:54 +0000
From:   Conor Dooley <conor.dooley@microchip.com>
To:     Song Shuai <suagrfillet@gmail.com>
CC:     <corbet@lwn.net>, <alexs@kernel.org>, <siyanteng@loongson.cn>,
        <robh@kernel.org>, <palmer@rivosinc.com>,
        <leyfoon.tan@starfivetech.com>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH] sched/doc: supplement CPU capacity with RISC-V
Message-ID: <Y/yoWt+Y7n8/A6m9@wendy>
References: <20230227105941.2749193-1-suagrfillet@gmail.com>
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On Mon, Feb 27, 2023 at 12:40:45PM +0000, Song Shuai wrote:
> Conor Dooley <conor.dooley@microchip.com> =E4=BA=8E2023=E5=B9=B42=E6=9C=
=8827=E6=97=A5=E5=91=A8=E4=B8=80 11:57=E5=86=99=E9=81=93=EF=BC=9A
> >
> > On Mon, Feb 27, 2023 at 06:59:41PM +0800, Song Shuai wrote:
> > > This commit 7d2078310cbf ("dt-bindings: arm: move cpu-capacity to a
> > > shared loation") updates some references about capacity-dmips-mhz
> >
> > Not requesting a respin for this, but mentioning commit 991994509ee9
> > ("dt-bindings: riscv: add a capacity-dmips-mhz cpu property") is
> > probably more relevant as a justification for this change.
> >
> Thanks for your correction, I'll pay attention next time.
>=20
> I have a question about the patch you mentioned:
> The patch uses cpu_scale per_cpu variable to store the CPU capacity
> through arch_topology,
> But arch_scale_cpu_capacity() interface seems not defined to deliver
> the cpu_scale to the scheduler
> In contrast, arm64 defines it as the topology_get_cpu_scale() in its
> arch/arm64/include/asm/topology.h.
> Is this an oversight or a particular purpose?

Intentional oversight I suppose? It wasn't my intention to do anything
other than document the property that people were already using in
their devicetrees (and finding bugs with!).
In retrospect, perhaps it is better if I un-review this patch until
we know it is plumbed into the scheduler properly?

Ley Foon Tan is the one that found the RISC-V bugs with this property in
their devicetree, so perhaps they've already done the work here?

Thanks,
Conor.

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