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From: "Wang, Yipeng1" <yipeng1.wang@intel.com>
To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"Richardson, Bruce" <bruce.richardson@intel.com>,
	"vguvva@caviumnetworks.com" <vguvva@caviumnetworks.com>,
	"brijesh.s.singh@gmail.com" <brijesh.s.singh@gmail.com>,
	nd <nd@arm.com>, "Tai, Charlie" <charlie.tai@intel.com>,
	"Wang, Ren" <ren.wang@intel.com>,
	"Gobriel, Sameh" <sameh.gobriel@intel.com>
Subject: Re: [dpdk-dev] [PATCH v4 0/8] Add read-write concurrency to rte_hash library
Date: Thu, 12 Jul 2018 01:31:24 +0000	[thread overview]
Message-ID: <D2C4A16CA39F7F4E8E384D204491D7A661478D25@ORSMSX105.amr.corp.intel.com> (raw)
In-Reply-To: <HE1PR0801MB19305166F112656040071BB7985B0@HE1PR0801MB1930.eurprd08.prod.outlook.com>

Hi, Honnappa,

Thanks for the comment.

RCU can handle one of the currency issue (key deletion while lookup) that has been discussed before, but we think it is not easy for RCU-alone to
protect reader from cuckoo path displacement. Also, RCU solution requires user interaction.

We agree that the current rwlock does not support preemptable writer. But a more advanced rwlock with priority could be
implemented in the future into the rwlock library.

Thanks
Yipeng

>-----Original Message-----
>From: Honnappa Nagarahalli [mailto:Honnappa.Nagarahalli@arm.com]
>Sent: Tuesday, July 10, 2018 11:00 AM
>To: Wang, Yipeng1 <yipeng1.wang@intel.com>; De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>
>Cc: dev@dpdk.org; Richardson, Bruce <bruce.richardson@intel.com>; vguvva@caviumnetworks.com; brijesh.s.singh@gmail.com; nd
><nd@arm.com>
>Subject: RE: [PATCH v4 0/8] Add read-write concurrency to rte_hash library
>
>Hi Yipeng/Pablo,
>	Apologies for my delayed comments
>
>-----Original Message-----
>From: Yipeng Wang <yipeng1.wang@intel.com>
>Sent: Monday, July 9, 2018 5:45 AM
>To: pablo.de.lara.guarch@intel.com
>Cc: dev@dpdk.org; yipeng1.wang@intel.com; bruce.richardson@intel.com; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
>vguvva@caviumnetworks.com; brijesh.s.singh@gmail.com
>Subject: [PATCH v4 0/8] Add read-write concurrency to rte_hash library
>
>This patch set adds the read-write concurrency support in rte_hash.
>A new flag value is added to indicate if read-write concurrency is needed during creation time. Test cases are implemented to do
>functional and performance tests.
>
>The new concurrency model is based on rte_rwlock. When Intel TSX is available and the users indicate to use it, the TM version of the
>rte_rwlock will be called. Both multi-writer and read-write concurrency are protected by the rte_rwlock instead of the x86 specific
>RTM instructions, so the x86 specific header rte_cuckoo_hash_x86.h is removed and the code is infused into the main .c file.
>
>IMO, at a high-level, there are two use cases for the rte_hash library:
>1) Writers are on control plane and data plane are readers
>2) Writers and readers are on data plane
>
>This distinction is required as in the case of 1) writers are pre-emptible. If I consider platforms without TSX (I do not know how Intel
>TSX works), the rte_rwlock implementation is blocking. A writer on the control plane can take the lock and get pre-empted. Since
>rte_rwlock is used for read-write concurrency, it will block the readers (on the data plane) for an extended duration. I think, support
>for RCU is required to solve this issue.
>
>

  reply	other threads:[~2018-07-12  1:31 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-08 10:51 [dpdk-dev] [PATCH v1 0/3] " Yipeng Wang
2018-06-08 10:51 ` [dpdk-dev] [PATCH v1 1/3] hash: add read and write concurrency support Yipeng Wang
2018-06-26 14:59   ` De Lara Guarch, Pablo
2018-06-08 10:51 ` [dpdk-dev] [PATCH v1 2/3] test: add test case for read write concurrency Yipeng Wang
2018-06-26 15:48   ` De Lara Guarch, Pablo
2018-06-08 10:51 ` [dpdk-dev] [PATCH v1 3/3] hash: add new API function to query the key count Yipeng Wang
2018-06-26 16:11   ` De Lara Guarch, Pablo
2018-06-29 12:24 ` [dpdk-dev] [PATCH v2 0/6] Add read-write concurrency to rte_hash library Yipeng Wang
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 1/6] hash: make duplicated code into functions Yipeng Wang
2018-07-06 10:04     ` De Lara Guarch, Pablo
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 2/6] hash: add read and write concurrency support Yipeng Wang
2018-07-06 17:11     ` De Lara Guarch, Pablo
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 3/6] test: add tests in hash table perf test Yipeng Wang
2018-07-06 17:17     ` De Lara Guarch, Pablo
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 4/6] test: add test case for read write concurrency Yipeng Wang
2018-07-06 17:31     ` De Lara Guarch, Pablo
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 5/6] hash: fix to have more accurate key slot size Yipeng Wang
2018-07-06 17:32     ` De Lara Guarch, Pablo
2018-06-29 12:24   ` [dpdk-dev] [PATCH v2 6/6] hash: add new API function to query the key count Yipeng Wang
2018-07-06 17:36     ` De Lara Guarch, Pablo
2018-07-06 19:46 ` [dpdk-dev] [PATCH v3 0/8] Add read-write concurrency to rte_hash library Yipeng Wang
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 1/8] hash: fix multiwriter lock memory allocation Yipeng Wang
2018-07-09 11:26     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 2/8] hash: fix a multi-writer bug Yipeng Wang
2018-07-09 14:16     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 3/8] hash: fix to have more accurate key slot size Yipeng Wang
2018-07-09 14:20     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 4/8] hash: make duplicated code into functions Yipeng Wang
2018-07-09 14:25     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 5/8] hash: add read and write concurrency support Yipeng Wang
2018-07-09 14:28     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 6/8] test: add tests in hash table perf test Yipeng Wang
2018-07-09 15:33     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 7/8] test: add test case for read write concurrency Yipeng Wang
2018-07-09 16:24     ` De Lara Guarch, Pablo
2018-07-06 19:46   ` [dpdk-dev] [PATCH v3 8/8] hash: add new API function to query the key count Yipeng Wang
2018-07-09 16:22     ` De Lara Guarch, Pablo
2018-07-09 10:44 ` [dpdk-dev] [PATCH v4 0/8] Add read-write concurrency to rte_hash library Yipeng Wang
2018-07-09 10:44   ` [dpdk-dev] [PATCH v4 1/8] hash: fix multiwriter lock memory allocation Yipeng Wang
2018-07-09 10:44   ` [dpdk-dev] [PATCH v4 2/8] hash: fix a multi-writer race condition Yipeng Wang
2018-07-09 10:44   ` [dpdk-dev] [PATCH v4 3/8] hash: fix key slot size accuracy Yipeng Wang
2018-07-09 10:44   ` [dpdk-dev] [PATCH v4 4/8] hash: make duplicated code into functions Yipeng Wang
2018-07-09 10:45   ` [dpdk-dev] [PATCH v4 5/8] hash: add read and write concurrency support Yipeng Wang
2018-07-09 10:45   ` [dpdk-dev] [PATCH v4 6/8] test: add tests in hash table perf test Yipeng Wang
2018-07-09 10:45   ` [dpdk-dev] [PATCH v4 7/8] test: add test case for read write concurrency Yipeng Wang
2018-07-09 10:45   ` [dpdk-dev] [PATCH v4 8/8] hash: add new API function to query the key count Yipeng Wang
2018-07-10 18:00   ` [dpdk-dev] [PATCH v4 0/8] Add read-write concurrency to rte_hash library Honnappa Nagarahalli
2018-07-12  1:31     ` Wang, Yipeng1 [this message]
2018-07-12  2:36       ` Honnappa Nagarahalli
2018-07-13  1:47         ` Wang, Yipeng1
2018-07-10 16:59 ` [dpdk-dev] [PATCH v5 " Yipeng Wang
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 1/8] hash: fix multiwriter lock memory allocation Yipeng Wang
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 2/8] hash: fix a multi-writer race condition Yipeng Wang
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 3/8] hash: fix key slot size accuracy Yipeng Wang
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 4/8] hash: make duplicated code into functions Yipeng Wang
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 5/8] hash: add read and write concurrency support Yipeng Wang
2018-07-11 20:49     ` Stephen Hemminger
2018-07-12  1:22       ` Wang, Yipeng1
2018-07-12 20:30         ` Thomas Monjalon
2018-07-13  1:55           ` Wang, Yipeng1
2018-08-17 12:51             ` ASM
2018-07-10 16:59   ` [dpdk-dev] [PATCH v5 6/8] test: add tests in hash table perf test Yipeng Wang
2018-07-10 17:00   ` [dpdk-dev] [PATCH v5 7/8] test: add test case for read write concurrency Yipeng Wang
2018-07-10 17:00   ` [dpdk-dev] [PATCH v5 8/8] hash: add new API function to query the key count Yipeng Wang
2018-07-12 21:03   ` [dpdk-dev] [PATCH v5 0/8] Add read-write concurrency to rte_hash library Thomas Monjalon

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