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Date: Mon, 5 Feb 2024 17:02:00 +1100
From: David Gibson <david@gibson.dropbear.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Subject: Re: [PATCH 03/24] checksum: align buffers
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On Fri, Feb 02, 2024 at 03:11:30PM +0100, Laurent Vivier wrote:
> if buffer is not aligned use sum_16b() only on the not aligned
> part, and then use csum() on the remaining part
>=20
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> checksum.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>=20
> diff --git a/checksum.c b/checksum.c
> index f21c9b7a14d1..c94980771c63 100644
> --- a/checksum.c
> +++ b/checksum.c
> @@ -407,7 +407,19 @@ less_than_128_bytes:
> __attribute__((optimize("-fno-strict-aliasing"))) /* See csum_16b() */
> uint16_t csum(const void *buf, size_t len, uint32_t init)
> {
> - return (uint16_t)~csum_fold(csum_avx2(buf, len, init));
> + intptr_t align =3D ((intptr_t)buf + 0x1f) & ~(intptr_t)0x1f;
Wonder if its worth adding an ALIGN_UP macro.
> + unsigned int pad =3D align - (intptr_t)buf;
> +
> + if (len < pad)
> + pad =3D len;
> +
> + if (pad)
> + init +=3D sum_16b(buf, pad);
> +
> + if (len > pad)
> + init =3D csum_avx2((void *)align, len - pad, init);
> +
> + return (uint16_t)~csum_fold(init);
> }
> =20
> #else /* __AVX2__ */
--=20
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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