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Date:   Mon, 14 Mar 2022 12:19:21 -0700
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To:     Kohei Tarumizu <tarumizu.kohei@fujitsu.com>,
        catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
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References: <20220311101940.3403607-1-tarumizu.kohei@fujitsu.com>
From:   Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH v2 0/8] Add hardware prefetch control driver for arm64 and
 x86
In-Reply-To: <20220311101940.3403607-1-tarumizu.kohei@fujitsu.com>
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On 3/11/22 02:19, Kohei Tarumizu wrote:
> The advantage of using this is improved performance. As an example of
> performance improvements, the results of running the Stream benchmark
> on the A64FX are described in section [Merit].

I take it that there are users out there today that are sufficiently
motivated by the increased performance that they just do "wrmsr 0x1a4
0x1234".

You talked about this in the "[Merit]" section.  But, that's a _little_
unconvincing.  I don't doubt that there is *a* workload out there that
can benefit from hardware prefetcher tweaks.

Do we really expect end users to run their workloads and tweak these
values to find something optimal for them?