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From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>,
	Andrew Pinski <pinskia@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] aarch64: Use memcpy_simd as the default memcpy
Date: Wed, 19 Oct 2022 12:31:57 +0000	[thread overview]
Message-ID: <AS4PR08MB79012199C16469C388D87124832B9@AS4PR08MB7901.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <84c7e095-239a-a504-ab7d-ef178051163c@linaro.org>

Hi Adhemerval,

On 13/10/22 09:28, Wilco Dijkstra via Libc-alpha wrote:
> Hi Andrew,
> 
>> This changes how neoverse-n2 is handled, is that expected?
>> That is neoverse-n2 was returning __memcpy_simd before and now will be
>> returning __memcpy_sve as n2 has SVE.
> 
> Yes, the SVE memcpy can be used by any CPU that supports SVE. Having this
> as a general rule is better than special casing every CPU.

> Maybe move this change to a different patch?

That if statement made no sense after the change, so I removed it altogether. Either
way, it doesn't seem large or important enough to warrant a separate patch. I could
add a note in the commit log, eg:

Since __memcpy_simd is the fastest memcpy on almost all cores, use it by default.
If SVE is available, a SVE memcpy will be used by default (including Neoverse N2).

Cheers,
Wilco

  reply	other threads:[~2022-10-19 12:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-12 15:19 Wilco Dijkstra
2022-10-12 19:12 ` Andrew Pinski
2022-10-13 12:28   ` Wilco Dijkstra
2022-10-13 12:30     ` Adhemerval Zanella Netto
2022-10-19 12:31       ` Wilco Dijkstra [this message]
2022-10-25 12:55         ` Szabolcs Nagy

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