DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Kinsella, Ray" <mdr@ashroe.eu>
To: Bruce Richardson <bruce.richardson@intel.com>,
	David Marchand <david.marchand@redhat.com>
Cc: Ruifeng Wang <ruifeng.wang@arm.com>,
	Vladimir Medvedkin <vladimir.medvedkin@intel.com>,
	John McNamara <john.mcnamara@intel.com>,
	Marko Kovacevic <marko.kovacevic@intel.com>,
	Neil Horman <nhorman@tuxdriver.com>, dev <dev@dpdk.org>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>,
	nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v5 1/3] lib/lpm: integrate RCU QSBR
Date: Tue, 30 Jun 2020 11:35:53 +0100
Message-ID: <0d1d3cd3-fdda-6f6f-125b-27d170683cdb@ashroe.eu> (raw)
In-Reply-To: <20200629125514.GC572@bricha3-MOBL.ger.corp.intel.com>



On 29/06/2020 13:55, Bruce Richardson wrote:
> On Mon, Jun 29, 2020 at 01:56:07PM +0200, David Marchand wrote:
>> On Mon, Jun 29, 2020 at 10:03 AM Ruifeng Wang <ruifeng.wang@arm.com> wrote:
>>>
>>> Currently, the tbl8 group is freed even though the readers might be
>>> using the tbl8 group entries. The freed tbl8 group can be reallocated
>>> quickly. This results in incorrect lookup results.
>>>
>>> RCU QSBR process is integrated for safe tbl8 group reclaim.
>>> Refer to RCU documentation to understand various aspects of
>>> integrating RCU library into other libraries.
>>>
>>> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
>>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>>> ---
>>>  doc/guides/prog_guide/lpm_lib.rst  |  32 +++++++
>>>  lib/librte_lpm/Makefile            |   2 +-
>>>  lib/librte_lpm/meson.build         |   1 +
>>>  lib/librte_lpm/rte_lpm.c           | 129 ++++++++++++++++++++++++++---
>>>  lib/librte_lpm/rte_lpm.h           |  59 +++++++++++++
>>>  lib/librte_lpm/rte_lpm_version.map |   6 ++
>>>  6 files changed, 216 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/doc/guides/prog_guide/lpm_lib.rst b/doc/guides/prog_guide/lpm_lib.rst
>>> index 1609a57d0..7cc99044a 100644
>>> --- a/doc/guides/prog_guide/lpm_lib.rst
>>> +++ b/doc/guides/prog_guide/lpm_lib.rst
>>> @@ -145,6 +145,38 @@ depending on whether we need to move to the next table or not.
>>>  Prefix expansion is one of the keys of this algorithm,
>>>  since it improves the speed dramatically by adding redundancy.
>>>
>>> +Deletion
>>> +~~~~~~~~
>>> +
>>> +When deleting a rule, a replacement rule is searched for. Replacement rule is an existing rule that has
>>> +the longest prefix match with the rule to be deleted, but has smaller depth.
>>> +
>>> +If a replacement rule is found, target tbl24 and tbl8 entries are updated to have the same depth and next hop
>>> +value with the replacement rule.
>>> +
>>> +If no replacement rule can be found, target tbl24 and tbl8 entries will be cleared.
>>> +
>>> +Prefix expansion is performed if the rule's depth is not exactly 24 bits or 32 bits.
>>> +
>>> +After deleting a rule, a group of tbl8s that belongs to the same tbl24 entry are freed in following cases:
>>> +
>>> +*   All tbl8s in the group are empty .
>>> +
>>> +*   All tbl8s in the group have the same values and with depth no greater than 24.
>>> +
>>> +Free of tbl8s have different behaviors:
>>> +
>>> +*   If RCU is not used, tbl8s are cleared and reclaimed immediately.
>>> +
>>> +*   If RCU is used, tbl8s are reclaimed when readers are in quiescent state.
>>> +
>>> +When the LPM is not using RCU, tbl8 group can be freed immediately even though the readers might be using
>>> +the tbl8 group entries. This might result in incorrect lookup results.
>>> +
>>> +RCU QSBR process is integrated for safe tbl8 group reclaimation. Application has certain responsibilities
>>> +while using this feature. Please refer to resource reclaimation framework of :ref:`RCU library <RCU_Library>`
>>> +for more details.
>>> +
>>
>> Would the lpm6 library benefit from the same?
>> Asking as I do not see much code shared between lpm and lpm6.
>>
>> [...]
>>
>>> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
>>> index 38ab512a4..41e9c49b8 100644
>>> --- a/lib/librte_lpm/rte_lpm.c
>>> +++ b/lib/librte_lpm/rte_lpm.c
>>> @@ -1,5 +1,6 @@
>>>  /* SPDX-License-Identifier: BSD-3-Clause
>>>   * Copyright(c) 2010-2014 Intel Corporation
>>> + * Copyright(c) 2020 Arm Limited
>>>   */
>>>
>>>  #include <string.h>
>>> @@ -245,13 +246,84 @@ rte_lpm_free(struct rte_lpm *lpm)
>>>                 TAILQ_REMOVE(lpm_list, te, next);
>>>
>>>         rte_mcfg_tailq_write_unlock();
>>> -
>>> +#ifdef ALLOW_EXPERIMENTAL_API
>>> +       if (lpm->dq)
>>> +               rte_rcu_qsbr_dq_delete(lpm->dq);
>>> +#endif
>>
>> All DPDK code under lib/ is compiled with the ALLOW_EXPERIMENTAL_API flag set.
>> There is no need to protect against this flag in rte_lpm.c.
>>
>> [...]
>>
>>> diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h
>>> index b9d49ac87..7889f21b3 100644
>>> --- a/lib/librte_lpm/rte_lpm.h
>>> +++ b/lib/librte_lpm/rte_lpm.h
>>
>>> @@ -130,6 +143,28 @@ struct rte_lpm {
>>>                         __rte_cache_aligned; /**< LPM tbl24 table. */
>>>         struct rte_lpm_tbl_entry *tbl8; /**< LPM tbl8 table. */
>>>         struct rte_lpm_rule *rules_tbl; /**< LPM rules. */
>>> +#ifdef ALLOW_EXPERIMENTAL_API
>>> +       /* RCU config. */
>>> +       struct rte_rcu_qsbr *v;         /* RCU QSBR variable. */
>>> +       enum rte_lpm_qsbr_mode rcu_mode;/* Blocking, defer queue. */
>>> +       struct rte_rcu_qsbr_dq *dq;     /* RCU QSBR defer queue. */
>>> +#endif
>>> +};
>>
>> This is more a comment/question for the lpm maintainers.
>>
>> Afaics, the rte_lpm structure is exported/public because of lookup
>> which is inlined.
>> But most of the structure can be hidden and stored in a private
>> structure that would embed the exposed rte_lpm.
>> The slowpath functions would only have to translate from publicly
>> exposed to internal representation (via container_of).
>>
>> This patch could do this and be the first step to hide the unneeded
>> exposure of other fields (later/in 20.11 ?).
>>
>> Thoughts?
>>
> Hiding as much of the structures as possible is always a good idea, so if
> that is possible in this patchset I would support such a move.
> 
> /Bruce
> 

Agreed - I acked the change as it doesn't break ABI compatibility.
Bruce and David's comments still hold for 20.11+. 

Ray K

  reply	other threads:[~2020-06-30 10:36 UTC|newest]

Thread overview: 137+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22  6:34 [dpdk-dev] [RFC PATCH 0/3] RCU integration with LPM library Ruifeng Wang
2019-08-22  6:34 ` [dpdk-dev] [RFC PATCH 1/3] doc/rcu: add RCU integration design details Ruifeng Wang
2019-08-22  6:34 ` [dpdk-dev] [RFC PATCH 2/3] lib/ring: add peek API Ruifeng Wang
2019-08-22  6:34 ` [dpdk-dev] [RFC PATCH 3/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2019-08-23  1:23   ` Stephen Hemminger
2019-08-26  3:11     ` Ruifeng Wang (Arm Technology China)
2019-08-26  5:32       ` Honnappa Nagarahalli
2019-08-22 15:52 ` [dpdk-dev] [RFC PATCH 0/3] RCU integration with LPM library Honnappa Nagarahalli
2019-09-06  9:45 ` [dpdk-dev] [PATCH v2 0/6] " Ruifeng Wang
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 1/6] doc/rcu: add RCU integration design details Ruifeng Wang
2019-09-06 19:44     ` Honnappa Nagarahalli
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 2/6] lib/ring: add peek API Ruifeng Wang
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 3/6] lib/lpm: integrate RCU QSBR Ruifeng Wang
2019-09-06 19:44     ` Honnappa Nagarahalli
2019-09-18 16:15     ` Medvedkin, Vladimir
2019-09-19  6:17       ` Ruifeng Wang (Arm Technology China)
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 4/6] app/test: add test case for LPM RCU integration Ruifeng Wang
2019-09-06 19:45     ` Honnappa Nagarahalli
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 5/6] test/lpm: reset total time Ruifeng Wang
2019-09-18 16:17     ` Medvedkin, Vladimir
2019-09-19  6:22       ` Ruifeng Wang (Arm Technology China)
2019-09-06  9:45   ` [dpdk-dev] [PATCH v2 6/6] test/lpm: add RCU integration performance tests Ruifeng Wang
2019-09-06 19:46     ` Honnappa Nagarahalli
2019-10-01  6:29   ` [dpdk-dev] [PATCH v3 0/3] Add RCU reclamation APIs Honnappa Nagarahalli
2019-10-01  6:29     ` [dpdk-dev] [PATCH v3 1/3] lib/ring: add peek API Honnappa Nagarahalli
2019-10-02 18:42       ` Ananyev, Konstantin
2019-10-03 19:49         ` Honnappa Nagarahalli
2019-10-07  9:01           ` Ananyev, Konstantin
2019-10-09  4:25             ` Honnappa Nagarahalli
2019-10-10 15:09               ` Ananyev, Konstantin
2019-10-11  5:03                 ` Honnappa Nagarahalli
2019-10-11 14:41                   ` Ananyev, Konstantin
2019-10-11 18:28                     ` Honnappa Nagarahalli
2019-10-13 20:09                       ` Ananyev, Konstantin
2019-10-14  4:11                         ` Honnappa Nagarahalli
2019-10-01  6:29     ` [dpdk-dev] [PATCH v3 2/3] lib/rcu: add resource reclamation APIs Honnappa Nagarahalli
2019-10-02 17:39       ` Ananyev, Konstantin
2019-10-03  6:29         ` Honnappa Nagarahalli
2019-10-03 12:26           ` Ananyev, Konstantin
2019-10-04  6:07             ` Honnappa Nagarahalli
2019-10-07 10:46               ` Ananyev, Konstantin
2019-10-13  4:35                 ` Honnappa Nagarahalli
2019-10-02 18:50       ` Ananyev, Konstantin
2019-10-03  6:42         ` Honnappa Nagarahalli
2019-10-03 11:52           ` Ananyev, Konstantin
2019-10-04 19:01       ` Medvedkin, Vladimir
2019-10-07 13:11       ` Medvedkin, Vladimir
2019-10-13  3:02         ` Honnappa Nagarahalli
2019-10-15 16:48           ` Medvedkin, Vladimir
2019-10-18  3:47             ` Honnappa Nagarahalli
2019-10-01  6:29     ` [dpdk-dev] [PATCH v3 3/3] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-03-29 20:57     ` [dpdk-dev] [PATCH v3 0/3] Add RCU reclamation APIs Thomas Monjalon
2020-03-30 17:37       ` Honnappa Nagarahalli
2020-04-03 18:41     ` [dpdk-dev] [PATCH v4 0/4] " Honnappa Nagarahalli
2020-04-03 18:41       ` [dpdk-dev] [PATCH v4 1/4] lib/rcu: add resource " Honnappa Nagarahalli
2020-04-07 17:39         ` Ananyev, Konstantin
2020-04-19 23:22           ` Honnappa Nagarahalli
2020-04-20  8:19             ` Ananyev, Konstantin
2020-04-03 18:41       ` [dpdk-dev] [PATCH v4 2/4] test/rcu: test cases for RCU defer queue APIs Honnappa Nagarahalli
2020-04-03 18:41       ` [dpdk-dev] [PATCH v4 3/4] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-04-03 18:41       ` [dpdk-dev] [PATCH v4 4/4] lib/rcu: add additional debug logs Honnappa Nagarahalli
2020-04-22  3:30     ` [dpdk-dev] [PATCH v5 0/4] Add RCU reclamation APIs Honnappa Nagarahalli
2020-04-22  3:30       ` [dpdk-dev] [PATCH v5 1/4] lib/rcu: add resource " Honnappa Nagarahalli
2020-04-22  8:36         ` Ananyev, Konstantin
2020-04-22  8:42           ` David Marchand
2020-04-22  8:51             ` David Marchand
2020-04-22  9:26               ` Ananyev, Konstantin
2020-04-22  3:30       ` [dpdk-dev] [PATCH v5 2/4] test/rcu: test cases for RCU defer queue APIs Honnappa Nagarahalli
2020-04-22  8:27         ` Ananyev, Konstantin
2020-04-22  3:30       ` [dpdk-dev] [PATCH v5 3/4] doc/rcu: add RCU integration design details Honnappa Nagarahalli
2020-04-22  3:30       ` [dpdk-dev] [PATCH v5 4/4] lib/rcu: add additional debug logs Honnappa Nagarahalli
2020-04-22  8:25         ` Ananyev, Konstantin
2020-04-22 18:46       ` [dpdk-dev] [PATCH v5 0/4] Add RCU reclamation APIs David Marchand
2019-10-01 18:28   ` [dpdk-dev] [PATCH v3 0/3] RCU integration with LPM library Honnappa Nagarahalli
2019-10-01 18:28     ` [dpdk-dev] [PATCH v3 1/3] lib/lpm: integrate RCU QSBR Honnappa Nagarahalli
2019-10-04 16:05       ` Medvedkin, Vladimir
2019-10-09  3:48         ` Honnappa Nagarahalli
2019-10-07  9:21       ` Ananyev, Konstantin
2019-10-13  4:36         ` Honnappa Nagarahalli
2019-10-15 11:15           ` Ananyev, Konstantin
2019-10-18  3:32             ` Honnappa Nagarahalli
2019-10-01 18:28     ` [dpdk-dev] [PATCH v3 2/3] app/test: add test case for LPM RCU integration Honnappa Nagarahalli
2019-10-01 18:28     ` [dpdk-dev] [PATCH v3 3/3] test/lpm: add RCU integration performance tests Honnappa Nagarahalli
2019-10-02 13:02       ` Aaron Conole
2019-10-03  9:09         ` Bruce Richardson
2020-06-08  5:16   ` [dpdk-dev] [PATCH v4 0/3] RCU integration with LPM library Ruifeng Wang
2020-06-08  5:16     ` [dpdk-dev] [PATCH v4 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-06-08 18:46       ` Honnappa Nagarahalli
2020-06-18 17:36         ` Medvedkin, Vladimir
2020-06-18 17:21       ` Medvedkin, Vladimir
2020-06-22  5:46         ` Ruifeng Wang
2020-06-23  4:34           ` Honnappa Nagarahalli
2020-06-08  5:16     ` [dpdk-dev] [PATCH v4 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-06-08  5:16     ` [dpdk-dev] [PATCH v4 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-06-29  8:02   ` [dpdk-dev] [PATCH v5 0/3] RCU integration with LPM library Ruifeng Wang
2020-06-29  8:02     ` [dpdk-dev] [PATCH v5 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-06-29 11:56       ` David Marchand
2020-06-29 12:55         ` Bruce Richardson
2020-06-30 10:35           ` Kinsella, Ray [this message]
2020-07-03  7:43         ` David Marchand
2020-07-04 17:00         ` Ruifeng Wang
2020-06-30 10:33       ` Kinsella, Ray
2020-06-29  8:02     ` [dpdk-dev] [PATCH v5 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-06-29  8:03     ` [dpdk-dev] [PATCH v5 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-07 14:40   ` [dpdk-dev] [PATCH v6 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-07 14:40     ` [dpdk-dev] [PATCH v6 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-07 14:40     ` [dpdk-dev] [PATCH v6 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-07 14:40     ` [dpdk-dev] [PATCH v6 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-07 15:15   ` [dpdk-dev] [PATCH v7 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-07 15:15     ` [dpdk-dev] [PATCH v7 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-08 12:36       ` Medvedkin, Vladimir
2020-07-08 14:30       ` David Marchand
2020-07-08 15:34         ` Ruifeng Wang
2020-07-07 15:15     ` [dpdk-dev] [PATCH v7 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-08 12:37       ` Medvedkin, Vladimir
2020-07-08 14:00         ` Ruifeng Wang
2020-07-07 15:15     ` [dpdk-dev] [PATCH v7 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-08 12:37       ` Medvedkin, Vladimir
2020-07-08 14:07         ` Ruifeng Wang
2020-07-09  8:02   ` [dpdk-dev] [PATCH v8 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-09  8:02     ` [dpdk-dev] [PATCH v8 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-09 11:49       ` David Marchand
2020-07-09 14:35         ` Ruifeng Wang
2020-07-09  8:02     ` [dpdk-dev] [PATCH v8 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-09  8:02     ` [dpdk-dev] [PATCH v8 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-09 15:42   ` [dpdk-dev] [PATCH v9 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-09 15:42     ` [dpdk-dev] [PATCH v9 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-09 15:42     ` [dpdk-dev] [PATCH v9 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-09 15:42     ` [dpdk-dev] [PATCH v9 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-10  2:22   ` [dpdk-dev] [PATCH v10 0/3] RCU integration with LPM library Ruifeng Wang
2020-07-10  2:22     ` [dpdk-dev] [PATCH v10 1/3] lib/lpm: integrate RCU QSBR Ruifeng Wang
2020-07-10  2:29       ` Ruifeng Wang
2020-07-10  2:22     ` [dpdk-dev] [PATCH v10 2/3] test/lpm: add LPM RCU integration functional tests Ruifeng Wang
2020-07-10  2:22     ` [dpdk-dev] [PATCH v10 3/3] test/lpm: add RCU integration performance tests Ruifeng Wang
2020-07-10  2:29       ` Ruifeng Wang
2020-07-10 12:21     ` [dpdk-dev] [PATCH v10 0/3] RCU integration with LPM library David Marchand
2020-07-10 14:34       ` Ruifeng Wang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=0d1d3cd3-fdda-6f6f-125b-27d170683cdb@ashroe.eu \
    --to=mdr@ashroe.eu \
    --cc=bruce.richardson@intel.com \
    --cc=david.marchand@redhat.com \
    --cc=dev@dpdk.org \
    --cc=honnappa.nagarahalli@arm.com \
    --cc=john.mcnamara@intel.com \
    --cc=konstantin.ananyev@intel.com \
    --cc=marko.kovacevic@intel.com \
    --cc=nd@arm.com \
    --cc=nhorman@tuxdriver.com \
    --cc=ruifeng.wang@arm.com \
    --cc=vladimir.medvedkin@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git