From: Richard Henderson <richard.henderson@linaro.org>
To: Alexander Monakov <amonakov@ispras.ru>
Cc: qemu-devel@nongnu.org, mmromanov@ispras.ru
Subject: Re: [PATCH v4 09/10] util/bufferiszero: Add simd acceleration for aarch64
Date: Thu, 15 Feb 2024 11:10:59 -1000 [thread overview]
Message-ID: <5e15fe47-94ce-4d25-a517-d766e70ac853@linaro.org> (raw)
In-Reply-To: <1e4d5081-d86b-84f5-20f7-8e48044b751a@ispras.ru>
On 2/15/24 08:46, Alexander Monakov wrote:
> Right, so we can pick the cheapest reduction method, and if I'm reading
> Neoverse-N1 SOG right, SHRN is marginally cheaper than ADDV (latency 2
> instead of 3), and it should be generally preferable on other cores, no?
Fair.
> For that matter, cannot UQXTN (unsigned saturating extract narrow) be
> used in place of CMEQ+ADDV here?
Interesting. I hadn't thought about using saturation to preserve non-zeroness like that.
Using 1 4-cycle insn instead of 2 2-cycle insns is interesting as well. I suppose, since
it's at the end of the dependency chain, the fact that it is restricted to the V1 pipe
matters not at all.
r~
next prev parent reply other threads:[~2024-02-15 21:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 8:14 [PATCH v4 00/10] Optimize buffer_is_zero Richard Henderson
2024-02-15 8:14 ` [PATCH v4 01/10] util/bufferiszero: Remove SSE4.1 variant Richard Henderson
2024-02-15 8:14 ` [PATCH v4 02/10] util/bufferiszero: Remove AVX512 variant Richard Henderson
2024-02-15 8:14 ` [PATCH v4 03/10] util/bufferiszero: Reorganize for early test for acceleration Richard Henderson
2024-02-15 8:14 ` [PATCH v4 04/10] util/bufferiszero: Remove useless prefetches Richard Henderson
2024-02-15 8:14 ` [PATCH v4 05/10] util/bufferiszero: Optimize SSE2 and AVX2 variants Richard Henderson
2024-02-15 8:14 ` [PATCH v4 06/10] util/bufferiszero: Improve scalar variant Richard Henderson
2024-02-15 8:14 ` [PATCH v4 07/10] util/bufferiszero: Introduce biz_accel_fn typedef Richard Henderson
2024-02-15 8:34 ` Philippe Mathieu-Daudé
2024-02-15 8:14 ` [PATCH v4 08/10] util/bufferiszero: Simplify test_buffer_is_zero_next_accel Richard Henderson
2024-02-15 8:40 ` Philippe Mathieu-Daudé
2024-02-15 8:14 ` [PATCH v4 09/10] util/bufferiszero: Add simd acceleration for aarch64 Richard Henderson
2024-02-15 8:47 ` Alexander Monakov
2024-02-15 17:47 ` Richard Henderson
2024-02-15 18:46 ` Alexander Monakov
2024-02-15 21:10 ` Richard Henderson [this message]
2024-02-15 8:14 ` [RFC PATCH v4 10/10] util/bufferiszero: Add sve " Richard Henderson
2024-02-16 9:33 ` Alex Bennée
2024-02-16 11:05 ` Alex Bennée
2024-02-15 8:57 ` [PATCH v4 00/10] Optimize buffer_is_zero Alexander Monakov
2024-02-15 21:16 ` Richard Henderson
2024-02-15 21:36 ` Alexander Monakov
2024-02-15 22:27 ` Richard Henderson
2024-02-15 23:37 ` Alexander Monakov
2024-02-16 8:11 ` Richard Henderson
2024-02-16 20:20 ` Alexander Monakov
2024-02-16 22:28 ` Richard Henderson
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