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From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Samuel Holland <samuel@sholland.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Prabhakar Lad <prabhakar.csengg@gmail.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH] clocksource/drivers/riscv: Increase the clock source rating
Date: Wed, 4 Jan 2023 23:29:06 +0100	[thread overview]
Message-ID: <a9dba647-b307-e60f-c31a-3ef7f949d23e@linaro.org> (raw)
In-Reply-To: <20221228004444.61568-1-samuel@sholland.org>

On 28/12/2022 01:44, Samuel Holland wrote:
> RISC-V provides an architectural clock source via the time CSR. This
> clock source exposes a 64-bit counter synchronized across all CPUs.
> Because it is accessed using a CSR, it is much more efficient to read
> than MMIO clock sources. For example, on the Allwinner D1, reading the
> sun4i timer in a loop takes 131 cycles/iteration, while reading the
> RISC-V time CSR takes only 5 cycles/iteration.
> 
> Adjust the RISC-V clock source rating so it is preferred over the
> various platform-specific MMIO clock sources.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
Applied, thanks

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  parent reply	other threads:[~2023-01-04 22:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-28  0:44 Samuel Holland
2022-12-28  3:58 ` Anup Patel
2022-12-28 23:29 ` Lad, Prabhakar
2022-12-29 16:22 ` Palmer Dabbelt
2022-12-29 17:21   ` Samuel Holland
2023-01-04 22:29 ` Daniel Lezcano [this message]
2023-02-13 18:26 ` [tip: timers/core] " tip-bot2 for Samuel Holland

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