Re: [dpdk-dev] [PATCH v3 3/9] ring: introduce RTS ring mode

["Wang, Haiyue" <haiyue.wang@intel.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Konstantin Ananyev
> Sent: Saturday, April 4, 2020 01:42
> To: dev@dpdk.org
> Cc: honnappa.nagarahalli@arm.com; david.marchand@redhat.com; jielong.zjl@antfin.com; Ananyev,
> Konstantin <konstantin.ananyev@intel.com>
> Subject: [dpdk-dev] [PATCH v3 3/9] ring: introduce RTS ring mode
> 
> Introduce relaxed tail sync (RTS) mode for MT ring synchronization.
> Aim to reduce stall times in case when ring is used on
> overcommited cpus (multiple active threads on the same cpu).
> The main difference from original MP/MC algorithm is that
> tail value is increased not by every thread that finished enqueue/dequeue,
> but only by the last one.
> That allows threads to avoid spinning on ring tail value,
> leaving actual tail value change to the last thread in the update queue.
> 
> check-abi.sh reports what I believe is a false-positive about
> ring cons/prod changes. As a workaround, devtools/libabigail.abignore is
> updated to suppress *struct ring* related errors.
> 
> Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> ---
>  devtools/libabigail.abignore           |   7 +
>  lib/librte_ring/Makefile               |   5 +-
>  lib/librte_ring/meson.build            |   5 +-
>  lib/librte_ring/rte_ring.c             | 100 +++++++-
>  lib/librte_ring/rte_ring.h             | 110 ++++++++-
>  lib/librte_ring/rte_ring_elem.h        |  86 ++++++-
>  lib/librte_ring/rte_ring_rts.h         | 316 +++++++++++++++++++++++++
>  lib/librte_ring/rte_ring_rts_elem.h    | 205 ++++++++++++++++
>  lib/librte_ring/rte_ring_rts_generic.h | 210 ++++++++++++++++
>  9 files changed, 1015 insertions(+), 29 deletions(-)
>  create mode 100644 lib/librte_ring/rte_ring_rts.h
>  create mode 100644 lib/librte_ring/rte_ring_rts_elem.h
>  create mode 100644 lib/librte_ring/rte_ring_rts_generic.h
> 


>  #ifdef __cplusplus
> diff --git a/lib/librte_ring/rte_ring_rts.h b/lib/librte_ring/rte_ring_rts.h
> new file mode 100644
> index 000000000..18404fe48
> --- /dev/null
> +++ b/lib/librte_ring/rte_ring_rts.h
> @@ -0,0 +1,316 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + *
> + * Copyright (c) 2010-2017 Intel Corporation
> + * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
> + * All rights reserved.
> + * Derived from FreeBSD's bufring.h

Find that it is buf_ring.h in real ;-)

> + * Used as BSD-3 Licensed with permission from Kip Macy.
> + */

> --
> 2.17.1