> -----Original Message----- > From: Morten Brørup <m...@smartsharesystems.com> > Sent: den 23 juni 2022 14:51 > To: Emil Berg <emil.b...@ericsson.com>; bruce.richard...@intel.com; > dev@dpdk.org > Cc: step...@networkplumber.org; sta...@dpdk.org; bugzi...@dpdk.org; > hof...@lysator.liu.se; olivier.m...@6wind.com > Subject: RE: [PATCH v4] net: fix checksum with unaligned buffer > > > From: Morten Brørup [mailto:m...@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: sta...@dpdk.org > > > > Signed-off-by: Morten Brørup <m...@smartsharesystems.com> > > Tested-by: Emil Berg <emil.b...@ericsson.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.
The test succeeded and I'm satisfied with the patch. I added 'Tested-by: Emil Berg <emil.b...@ericsson.com>' to the patch above, hopefully as you intended.
