From: Stephen Hemminger <stephen@networkplumber.org>
To: Gage Eads <gage.eads@intel.com>
Cc: dev@dpdk.org, olivier.matz@6wind.com, arybchenko@solarflare.com,
bruce.richardson@intel.com, konstantin.ananyev@intel.com
Subject: Re: [dpdk-dev] [PATCH 1/6] ring: change head and tail to pointer-width size
Date: Thu, 10 Jan 2019 20:38:33 -0800 [thread overview]
Message-ID: <20190110203833.3e6a6ea2@hermes.lan> (raw)
In-Reply-To: <20190110210122.24889-2-gage.eads@intel.com>
On Thu, 10 Jan 2019 15:01:17 -0600
Gage Eads <gage.eads@intel.com> wrote:
> For 64-bit architectures, doubling the head and tail index widths greatly
> increases the time it takes for them to wrap-around (with current CPU
> speeds, it won't happen within the author's lifetime). This is important in
> avoiding the ABA problem -- in which a thread mistakes reading the same
> tail index in two accesses to mean that the ring was not modified in the
> intervening time -- in the upcoming non-blocking ring implementation. Using
> a 64-bit index makes the possibility of this occurring effectively zero.
>
> I tested this commit's performance impact with an x86_64 build on a
> dual-socket Xeon E5-2699 v4 using ring_perf_autotest, and the change made
> no significant difference -- the few differences appear to be system noise.
> (The test ran on isolcpus cores using a tickless scheduler, but some
> variation was stll observed.) Each test was run three times and the results
> were averaged:
>
> | 64b head/tail cycle cost minus
> Test | 32b head/tail cycle cost
> ------------------------------------------------------------------
> SP/SC single enq/dequeue | 0.33
> MP/MC single enq/dequeue | 0.00
> SP/SC burst enq/dequeue (size 8) | 0.00
> MP/MC burst enq/dequeue (size 8) | 1.00
> SP/SC burst enq/dequeue (size 32) | 0.00
> MP/MC burst enq/dequeue (size 32) | -1.00
> SC empty dequeue | 0.01
> MC empty dequeue | 0.00
>
> Single lcore:
> SP/SC bulk enq/dequeue (size 8) | -0.36
> MP/MC bulk enq/dequeue (size 8) | 0.99
> SP/SC bulk enq/dequeue (size 32) | -0.40
> MP/MC bulk enq/dequeue (size 32) | -0.57
>
> Two physical cores:
> SP/SC bulk enq/dequeue (size 8) | -0.49
> MP/MC bulk enq/dequeue (size 8) | 0.19
> SP/SC bulk enq/dequeue (size 32) | -0.28
> MP/MC bulk enq/dequeue (size 32) | -0.62
>
> Two NUMA nodes:
> SP/SC bulk enq/dequeue (size 8) | 3.25
> MP/MC bulk enq/dequeue (size 8) | 1.87
> SP/SC bulk enq/dequeue (size 32) | -0.44
> MP/MC bulk enq/dequeue (size 32) | -1.10
>
> An earlier version of this patch changed the head and tail indexes to
> uint64_t, but that caused a performance drop on 32-bit builds. With
> uintptr_t, no performance difference is observed on an i686 build.
>
> Signed-off-by: Gage Eads <gage.eads@intel.com>
> ---
> lib/librte_eventdev/rte_event_ring.h | 6 +++---
> lib/librte_ring/rte_ring.c | 10 +++++-----
> lib/librte_ring/rte_ring.h | 20 ++++++++++----------
> lib/librte_ring/rte_ring_generic.h | 16 +++++++++-------
> 4 files changed, 27 insertions(+), 25 deletions(-)
>
> diff --git a/lib/librte_eventdev/rte_event_ring.h b/lib/librte_eventdev/rte_event_ring.h
> index 827a3209e..eae70f904 100644
> --- a/lib/librte_eventdev/rte_event_ring.h
> +++ b/lib/librte_eventdev/rte_event_ring.h
> @@ -1,5 +1,5 @@
> /* SPDX-License-Identifier: BSD-3-Clause
> - * Copyright(c) 2016-2017 Intel Corporation
> + * Copyright(c) 2016-2019 Intel Corporation
> */
>
> /**
> @@ -88,7 +88,7 @@ rte_event_ring_enqueue_burst(struct rte_event_ring *r,
> const struct rte_event *events,
> unsigned int n, uint16_t *free_space)
> {
> - uint32_t prod_head, prod_next;
> + uintptr_t prod_head, prod_next;
> uint32_t free_entries;
>
> n = __rte_ring_move_prod_head(&r->r, r->r.prod.single, n,
> @@ -129,7 +129,7 @@ rte_event_ring_dequeue_burst(struct rte_event_ring *r,
> struct rte_event *events,
> unsigned int n, uint16_t *available)
> {
> - uint32_t cons_head, cons_next;
> + uintptr_t cons_head, cons_next;
> uint32_t entries;
>
> n = __rte_ring_move_cons_head(&r->r, r->r.cons.single, n,
> diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
> index d215acecc..b15ee0eb3 100644
> --- a/lib/librte_ring/rte_ring.c
> +++ b/lib/librte_ring/rte_ring.c
> @@ -1,6 +1,6 @@
> /* SPDX-License-Identifier: BSD-3-Clause
> *
> - * Copyright (c) 2010-2015 Intel Corporation
> + * Copyright (c) 2010-2019 Intel Corporation
> * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org
> * All rights reserved.
> * Derived from FreeBSD's bufring.h
> @@ -227,10 +227,10 @@ rte_ring_dump(FILE *f, const struct rte_ring *r)
> fprintf(f, " flags=%x\n", r->flags);
> fprintf(f, " size=%"PRIu32"\n", r->size);
> fprintf(f, " capacity=%"PRIu32"\n", r->capacity);
> - fprintf(f, " ct=%"PRIu32"\n", r->cons.tail);
> - fprintf(f, " ch=%"PRIu32"\n", r->cons.head);
> - fprintf(f, " pt=%"PRIu32"\n", r->prod.tail);
> - fprintf(f, " ph=%"PRIu32"\n", r->prod.head);
> + fprintf(f, " ct=%"PRIuPTR"\n", r->cons.tail);
> + fprintf(f, " ch=%"PRIuPTR"\n", r->cons.head);
> + fprintf(f, " pt=%"PRIuPTR"\n", r->prod.tail);
> + fprintf(f, " ph=%"PRIuPTR"\n", r->prod.head);
> fprintf(f, " used=%u\n", rte_ring_count(r));
> fprintf(f, " avail=%u\n", rte_ring_free_count(r));
> }
> diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
> index af5444a9f..12af64e13 100644
> --- a/lib/librte_ring/rte_ring.h
> +++ b/lib/librte_ring/rte_ring.h
> @@ -1,6 +1,6 @@
> /* SPDX-License-Identifier: BSD-3-Clause
> *
> - * Copyright (c) 2010-2017 Intel Corporation
> + * Copyright (c) 2010-2019 Intel Corporation
> * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
> * All rights reserved.
> * Derived from FreeBSD's bufring.h
> @@ -65,8 +65,8 @@ struct rte_memzone; /* forward declaration, so as not to require memzone.h */
>
> /* structure to hold a pair of head/tail values and other metadata */
> struct rte_ring_headtail {
> - volatile uint32_t head; /**< Prod/consumer head. */
> - volatile uint32_t tail; /**< Prod/consumer tail. */
> + volatile uintptr_t head; /**< Prod/consumer head. */
> + volatile uintptr_t tail; /**< Prod/consumer tail. */
> uint32_t single; /**< True if single prod/cons */
> };
Isn't this a major ABI change which will break existing applications?
next prev parent reply other threads:[~2019-01-11 4:38 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 21:01 [dpdk-dev] [PATCH 0/6] Add non-blocking ring Gage Eads
2019-01-10 21:01 ` [dpdk-dev] [PATCH 1/6] ring: change head and tail to pointer-width size Gage Eads
2019-01-11 4:38 ` Stephen Hemminger [this message]
2019-01-11 19:07 ` Eads, Gage
2019-01-11 10:25 ` Burakov, Anatoly
2019-01-11 19:12 ` Eads, Gage
2019-01-11 19:55 ` Stephen Hemminger
2019-01-15 15:48 ` Eads, Gage
2019-01-11 10:40 ` Burakov, Anatoly
2019-01-11 10:58 ` Bruce Richardson
2019-01-11 11:30 ` Burakov, Anatoly
[not found] ` <20190111115851.GC3336@bricha3-MOBL.ger.corp.intel.com>
2019-01-11 19:27 ` Eads, Gage
2019-01-21 14:14 ` Burakov, Anatoly
2019-01-22 18:27 ` Eads, Gage
2019-01-10 21:01 ` [dpdk-dev] [PATCH 2/6] ring: add a non-blocking implementation Gage Eads
2019-01-10 21:01 ` [dpdk-dev] [PATCH 3/6] test_ring: add non-blocking ring autotest Gage Eads
2019-01-10 21:01 ` [dpdk-dev] [PATCH 4/6] test_ring_perf: add non-blocking ring perf test Gage Eads
2019-01-10 21:01 ` [dpdk-dev] [PATCH 5/6] mempool/ring: add non-blocking ring handlers Gage Eads
2019-01-13 13:43 ` Andrew Rybchenko
2019-01-10 21:01 ` [dpdk-dev] [PATCH 6/6] doc: add NB ring comment to EAL "known issues" Gage Eads
2019-01-11 2:51 ` Varghese, Vipin
2019-01-11 19:30 ` Eads, Gage
2019-01-14 0:07 ` Varghese, Vipin
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 0/5] Add non-blocking ring Gage Eads
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 1/5] ring: change head and tail to pointer-width size Gage Eads
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 2/5] ring: add a non-blocking implementation Gage Eads
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 3/5] test_ring: add non-blocking ring autotest Gage Eads
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 4/5] test_ring_perf: add non-blocking ring perf test Gage Eads
2019-01-15 23:52 ` [dpdk-dev] [PATCH v2 5/5] mempool/ring: add non-blocking ring handlers Gage Eads
2019-01-16 0:26 ` [dpdk-dev] [PATCH v2 0/5] Add non-blocking ring Stephen Hemminger
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 " Gage Eads
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 1/5] ring: add 64-bit headtail structure Gage Eads
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 2/5] ring: add a non-blocking implementation Gage Eads
2019-01-22 10:12 ` Ola Liljedahl
2019-01-22 14:49 ` Ola Liljedahl
2019-01-22 21:31 ` Eads, Gage
2019-01-23 10:16 ` Ola Liljedahl
2019-01-25 17:21 ` Eads, Gage
2019-01-28 10:35 ` Ola Liljedahl
2019-01-28 18:54 ` Eads, Gage
2019-01-28 22:31 ` Ola Liljedahl
2019-01-28 13:34 ` Jerin Jacob Kollanukkaran
2019-01-28 13:43 ` Ola Liljedahl
2019-01-28 14:04 ` Jerin Jacob Kollanukkaran
2019-01-28 14:06 ` Ola Liljedahl
2019-01-28 18:59 ` Eads, Gage
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 3/5] test_ring: add non-blocking ring autotest Gage Eads
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 4/5] test_ring_perf: add non-blocking ring perf test Gage Eads
2019-01-18 15:23 ` [dpdk-dev] [PATCH v3 5/5] mempool/ring: add non-blocking ring handlers Gage Eads
2019-01-22 9:27 ` [dpdk-dev] [PATCH v3 0/5] Add non-blocking ring Ola Liljedahl
2019-01-22 10:15 ` Ola Liljedahl
2019-01-22 19:15 ` Eads, Gage
2019-01-23 16:02 ` Jerin Jacob Kollanukkaran
2019-01-23 16:29 ` Ola Liljedahl
2019-01-28 13:10 ` [dpdk-dev] [EXT] " Jerin Jacob Kollanukkaran
2019-01-25 5:20 ` [dpdk-dev] " Honnappa Nagarahalli
2019-01-25 17:42 ` Eads, Gage
2019-01-25 17:56 ` Eads, Gage
2019-01-28 10:41 ` Ola Liljedahl
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 " Gage Eads
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 1/5] ring: add 64-bit headtail structure Gage Eads
2019-01-29 12:56 ` Ola Liljedahl
2019-01-30 4:26 ` Eads, Gage
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 2/5] ring: add a non-blocking implementation Gage Eads
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 3/5] test_ring: add non-blocking ring autotest Gage Eads
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 4/5] test_ring_perf: add non-blocking ring perf test Gage Eads
2019-01-28 18:14 ` [dpdk-dev] [PATCH v4 5/5] mempool/ring: add non-blocking ring handlers Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 0/6] Add lock-free ring and mempool handler Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 1/6] ring: add a pointer-width headtail structure Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 2/6] ring: add a ring start marker Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 3/6] ring: add a lock-free implementation Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 4/6] test_ring: add lock-free ring autotest Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 5/6] test_ring_perf: add lock-free ring perf test Gage Eads
2019-03-05 17:40 ` [dpdk-dev] [PATCH v5 6/6] mempool/ring: add lock-free ring handlers Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 0/6] Add lock-free ring and mempool handler Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 1/6] ring: add a pointer-width headtail structure Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 2/6] ring: add a ring start marker Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 3/6] ring: add a lock-free implementation Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 4/6] test_ring: add lock-free ring autotest Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 5/6] test_ring_perf: add lock-free ring perf test Gage Eads
2019-03-06 15:03 ` [dpdk-dev] [PATCH v6 6/6] mempool/ring: add lock-free ring handlers Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 0/6] Add lock-free ring and mempool handler Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 1/6] ring: add a pointer-width headtail structure Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 2/6] ring: add a ring start marker Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 3/6] ring: add a lock-free implementation Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-19 15:50 ` Stephen Hemminger
2019-03-19 15:50 ` Stephen Hemminger
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 4/6] test_ring: add lock-free ring autotest Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 5/6] test_ring_perf: add lock-free ring perf test Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:35 ` [dpdk-dev] [PATCH v7 6/6] mempool/ring: add lock-free ring handlers Gage Eads
2019-03-18 21:35 ` Gage Eads
2019-03-18 21:49 ` [dpdk-dev] [PATCH v7 0/6] Add lock-free ring and mempool handler Eads, Gage
2019-03-18 21:49 ` Eads, Gage
2019-03-19 15:51 ` Stephen Hemminger
2019-03-19 15:51 ` Stephen Hemminger
2019-04-01 19:23 ` Eads, Gage
2019-04-01 19:23 ` Eads, Gage
2019-04-02 10:16 ` Ola Liljedahl
2019-04-02 10:16 ` Ola Liljedahl
2019-04-04 22:28 ` Eads, Gage
2019-04-04 22:28 ` Eads, Gage
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 " Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 1/6] ring: add a pointer-width headtail structure Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 2/6] ring: add a ring start marker Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 3/6] ring: add a lock-free implementation Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 4/6] test_ring: add lock-free ring autotest Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 5/6] test_ring_perf: add lock-free ring perf test Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-03-19 1:20 ` [dpdk-dev] [PATCH v8 6/6] mempool/ring: add lock-free ring handlers Gage Eads
2019-03-19 1:20 ` Gage Eads
2019-04-03 16:46 ` [dpdk-dev] [PATCH v8 0/6] Add lock-free ring and mempool handler Thomas Monjalon
2019-04-03 16:46 ` Thomas Monjalon
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