From: "Morten Brørup" <mb@smartsharesystems.com>
To: <emil.berg@ericsson.com>, <bruce.richardson@intel.com>, <dev@dpdk.org>
Cc: <stephen@networkplumber.org>, <stable@dpdk.org>,
<bugzilla@dpdk.org>, <hofors@lysator.liu.se>,
<olivier.matz@6wind.com>
Subject: RE: [PATCH v4] net: fix checksum with unaligned buffer
Date: Thu, 23 Jun 2022 14:51:12 +0200 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D87169@smartserver.smartshare.dk> (raw)
In-Reply-To: <20220623123900.38283-1-mb@smartsharesystems.com>
> From: Morten Brørup [mailto:mb@smartsharesystems.com]
> Sent: Thursday, 23 June 2022 14.39
>
> With this patch, the checksum can be calculated on an unaligned buffer.
> I.e. the buf parameter is no longer required to be 16 bit aligned.
>
> The checksum is still calculated using a 16 bit aligned pointer, so the
> compiler can auto-vectorize the function's inner loop.
>
> When the buffer is unaligned, the first byte of the buffer is handled
> separately. Furthermore, the calculated checksum of the buffer is byte
> shifted before being added to the initial checksum, to compensate for
> the
> checksum having been calculated on the buffer shifted by one byte.
>
> v4:
> * Add copyright notice.
> * Include stdbool.h (Emil Berg).
> * Use RTE_PTR_ADD (Emil Berg).
> * Fix one more typo in commit message. Is 'unligned' even a word?
> v3:
> * Remove braces from single statement block.
> * Fix typo in commit message.
> v2:
> * Do not assume that the buffer is part of an aligned packet buffer.
>
> Bugzilla ID: 1035
> Cc: stable@dpdk.org
>
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> ---
> lib/net/rte_ip.h | 32 +++++++++++++++++++++++++++-----
> 1 file changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/lib/net/rte_ip.h b/lib/net/rte_ip.h
> index b502481670..738d643da0 100644
> --- a/lib/net/rte_ip.h
> +++ b/lib/net/rte_ip.h
> @@ -3,6 +3,7 @@
> * The Regents of the University of California.
> * Copyright(c) 2010-2014 Intel Corporation.
> * Copyright(c) 2014 6WIND S.A.
> + * Copyright(c) 2022 SmartShare Systems.
> * All rights reserved.
> */
>
> @@ -15,6 +16,7 @@
> * IP-related defines
> */
>
> +#include <stdbool.h>
> #include <stdint.h>
>
> #ifdef RTE_EXEC_ENV_WINDOWS
> @@ -162,20 +164,40 @@ __rte_raw_cksum(const void *buf, size_t len,
> uint32_t sum)
> {
> /* extend strict-aliasing rules */
> typedef uint16_t __attribute__((__may_alias__)) u16_p;
> - const u16_p *u16_buf = (const u16_p *)buf;
> - const u16_p *end = u16_buf + len / sizeof(*u16_buf);
> + const u16_p *u16_buf;
> + const u16_p *end;
> + uint32_t bsum = 0;
> + const bool unaligned = (uintptr_t)buf & 1;
> +
> + /* if buffer is unaligned, keeping it byte order independent */
> + if (unlikely(unaligned)) {
> + uint16_t first = 0;
> + if (unlikely(len == 0))
> + return 0;
> + ((unsigned char *)&first)[1] = *(const unsigned char *)buf;
> + bsum += first;
> + buf = RTE_PTR_ADD(buf, 1);
> + len--;
> + }
>
> + /* aligned access for compiler auto-vectorization */
> + u16_buf = (const u16_p *)buf;
> + end = u16_buf + len / sizeof(*u16_buf);
> for (; u16_buf != end; ++u16_buf)
> - sum += *u16_buf;
> + bsum += *u16_buf;
>
> /* if length is odd, keeping it byte order independent */
> if (unlikely(len % 2)) {
> uint16_t left = 0;
> *(unsigned char *)&left = *(const unsigned char *)end;
> - sum += left;
> + bsum += left;
> }
>
> - return sum;
> + /* if buffer is unaligned, swap the checksum bytes */
> + if (unlikely(unaligned))
> + bsum = (bsum & 0xFF00FF00) >> 8 | (bsum & 0x00FF00FF) << 8;
> +
> + return sum + bsum;
> }
>
> /**
> --
> 2.17.1
@Emil, thank you for thoroughly reviewing the previous versions.
If your test succeeds and you are satisfied with the patch, remember to reply with a "Tested-by" tag for patchwork.
next prev parent reply other threads:[~2022-06-23 12:51 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <98CBD80474FA8B44BF855DF32C47DC35D87139@smartserver.smartshare.dk>
2022-06-17 8:45 ` [PATCH] " Morten Brørup
2022-06-17 9:06 ` Morten Brørup
2022-06-20 10:37 ` Emil Berg
2022-06-20 10:57 ` Morten Brørup
2022-06-21 7:16 ` Emil Berg
2022-06-21 8:05 ` Morten Brørup
2022-06-21 8:23 ` Bruce Richardson
2022-06-21 9:35 ` Morten Brørup
2022-06-22 6:26 ` Emil Berg
2022-06-22 9:18 ` Bruce Richardson
2022-06-22 11:26 ` Morten Brørup
2022-06-22 12:25 ` Emil Berg
2022-06-22 14:01 ` Morten Brørup
2022-06-22 14:03 ` Emil Berg
2022-06-23 5:21 ` Emil Berg
2022-06-23 7:01 ` Morten Brørup
2022-06-23 11:39 ` Emil Berg
2022-06-23 12:18 ` Morten Brørup
2022-06-22 13:44 ` [PATCH v2] " Morten Brørup
2022-06-22 13:54 ` [PATCH v3] " Morten Brørup
2022-06-23 12:39 ` [PATCH v4] " Morten Brørup
2022-06-23 12:51 ` Morten Brørup [this message]
2022-06-27 7:56 ` Emil Berg
2022-06-27 10:54 ` Morten Brørup
2022-06-27 12:28 ` Mattias Rönnblom
2022-06-27 12:46 ` Emil Berg
2022-06-27 12:50 ` Emil Berg
2022-06-27 13:22 ` Morten Brørup
2022-06-27 17:22 ` Mattias Rönnblom
2022-06-27 20:21 ` Morten Brørup
2022-06-28 6:28 ` Mattias Rönnblom
2022-06-30 16:28 ` Morten Brørup
2022-07-07 15:21 ` Stanisław Kardach
2022-07-07 18:34 ` [PATCH 1/2] app/test: add cksum performance test Mattias Rönnblom
2022-07-07 18:34 ` [PATCH 2/2] net: have checksum routines accept unaligned data Mattias Rönnblom
2022-07-07 21:44 ` Morten Brørup
2022-07-08 12:43 ` Mattias Rönnblom
2022-07-08 12:56 ` [PATCH v2 1/2] app/test: add cksum performance test Mattias Rönnblom
2022-07-08 12:56 ` [PATCH v2 2/2] net: have checksum routines accept unaligned data Mattias Rönnblom
2022-07-08 14:44 ` Ferruh Yigit
2022-07-11 9:53 ` Olivier Matz
2022-07-11 10:53 ` Mattias Rönnblom
2022-07-11 9:47 ` [PATCH v2 1/2] app/test: add cksum performance test Olivier Matz
2022-07-11 10:42 ` Mattias Rönnblom
2022-07-11 11:33 ` Olivier Matz
2022-07-11 12:11 ` [PATCH v3 " Mattias Rönnblom
2022-07-11 12:11 ` [PATCH v3 2/2] net: have checksum routines accept unaligned data Mattias Rönnblom
2022-07-11 13:25 ` Olivier Matz
2022-08-08 9:25 ` Mattias Rönnblom
2022-09-20 12:09 ` Mattias Rönnblom
2022-09-20 16:10 ` Thomas Monjalon
2022-07-11 13:20 ` [PATCH v3 1/2] app/test: add cksum performance test Olivier Matz
2022-07-08 13:02 ` [PATCH 2/2] net: have checksum routines accept unaligned data Morten Brørup
2022-07-08 13:52 ` Mattias Rönnblom
2022-07-08 14:10 ` Bruce Richardson
2022-07-08 14:30 ` Morten Brørup
2022-06-30 17:41 ` [PATCH v4] net: fix checksum with unaligned buffer Stephen Hemminger
2022-06-30 17:45 ` Stephen Hemminger
2022-07-01 4:11 ` Emil Berg
2022-07-01 16:50 ` Morten Brørup
2022-07-01 17:04 ` Stephen Hemminger
2022-07-01 20:46 ` Morten Brørup
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