Re: [PATCH v2 0/4] crypto: rockchip: Add RK356x/RK3588 cryptographic offloader

From: "Diederik de Haas" <diederik@cknow-tech.com>
To: "Eric Biggers" <ebiggers@kernel.org>,
	"Diederik de Haas" <diederik@cknow-tech.com>
Cc: "Dawid Olesinski" <dawidro@gmail.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Corentin Labbe" <clabbe@baylibre.com>,
	<linux-crypto@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-rockchip@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/4] crypto: rockchip: Add RK356x/RK3588 cryptographic offloader
Date: Tue, 18 Aug 2026 22:23:18 +0200	[thread overview]
Message-ID: <DKSCMAUXS10I.2AB9KERO16FRG@cknow-tech.com> (raw)
In-Reply-To: <20260818200454.GA2718123@google.com>

On Tue Aug 18, 2026 at 10:04 PM CEST, Eric Biggers wrote:
> tcrypt.c reports cycle counts from get_cycles(), which has an
> architecture-dependent meaning.  On x86_64 it is something approximating
> the CPU cycles (3-5 GHz) whereas on arm64 it is the ARM Generic Timer
> which tends to be around 24 MHz or so, over 100 times slower than the
> actual CPU.  So 9044 vs 115 "cycles" for x86_64 vs arm64 sounds about
> expected, and they suggest the real times are likely similar but
> slightly faster on x86_64 as expected.

Phew, thanks for the explanation :-)

> This sort of thing is why benchmarks usually should measure real time.
> The legacy module tcrypt.c unfortunately uses get_cycles() instead.

What would be a better/non-legacy way to test crypto performance?
Is that documented somewhere?

Cheers,
  Diederik