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From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: Stephen Hemminger <stephen@networkplumber.org>,
	Jerin Jacob <jerinjacobk@gmail.com>
Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>,
	dpdk-dev <dev@dpdk.org>, Olivier Matz <olivier.matz@6wind.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	nd <nd@arm.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [RFC 0/6] New sync modes for ring
Date: Mon, 24 Feb 2020 20:52:51 +0000	[thread overview]
Message-ID: <VE1PR08MB51490B89EE7E1381FF87C35098EC0@VE1PR08MB5149.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20200224113529.4c1c94ab@hermes.lan>



> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Stephen Hemminger
> Sent: Monday, February 24, 2020 1:35 PM
> To: Jerin Jacob <jerinjacobk@gmail.com>
> Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>; dpdk-dev
> <dev@dpdk.org>; Olivier Matz <olivier.matz@6wind.com>
> Subject: Re: [dpdk-dev] [RFC 0/6] New sync modes for ring
> 
> On Mon, 24 Feb 2020 23:29:57 +0530
> Jerin Jacob <jerinjacobk@gmail.com> wrote:
> 
> > On Mon, Feb 24, 2020 at 10:29 PM Stephen Hemminger
> > <stephen@networkplumber.org> wrote:
> > >
> > > On Mon, 24 Feb 2020 11:35:09 +0000
> > > Konstantin Ananyev <konstantin.ananyev@intel.com> wrote:
> > >
> > > > Upfront note - that RFC is not a complete patch.
> > > > It introduces an ABI breakage, plus it doesn't update ring_elem
> > > > code properly, etc.
> > > > I plan to deal with all these things in later versions.
> > > > Right now I seek an initial feedback about proposed ideas.
> > > > Would also ask people to repeat performance tests (see below) on
> > > > their platforms to confirm the impact.
> > > >
> > > > More and more customers use(/try to use) DPDK based apps within
> > > > overcommitted systems (multiple acttive threads over same pysical
> cores):
> > > > VM, container deployments, etc.
> > > > One quite common problem they hit: Lock-Holder-Preemption with
> rte_ring.
> > > > LHP is quite a common problem for spin-based sync primitives
> > > > (spin-locks, etc.) on overcommitted systems.
> > > > The situation gets much worse when some sort of fair-locking
> > > > technique is used (ticket-lock, etc.).
> > > > As now not only lock-owner but also lock-waiters scheduling order
> > > > matters a lot.
> > > > This is a well-known problem for kernel within VMs:
> > > > http://www-archive.xenproject.org/files/xensummitboston08/LHP.pdf
> > > > https://www.cs.hs-rm.de/~kaiser/events/wamos2017/Slides/selcuk.pdf
> > > > The problem with rte_ring is that while head accusion is sort of
> > > > un-fair locking, waiting on tail is very similar to ticket lock
> > > > schema - tail has to be updated in particular order.
> > > > That makes current rte_ring implementation to perform really pure
> > > > on some overcommited scenarios.
> > >
> > > Rather than reform rte_ring to fit this scenario, it would make more
> > > sense to me to introduce another primitive. The current lockless
> > > ring performs very well for the isolated thread model that DPDK was
> > > built around. This looks like a case of customers violating the
> > > usage model of the DPDK and then being surprised at the fallout.
> >
> > I agree with Stephen here.
> >
> > I think, adding more runtime check in the enqueue() and dequeue() will
> > have a bad effect on the low-end cores too.
> > But I agree with the problem statement that in the virtualization use
> > case, It may be possible to have N virtual cores runs on a physical
> > core.
> >
> > IMO, The best solution would be keeping the ring API same and have a
> > different flavor in "compile-time". Something like liburcu did for
> > accommodating different flavors.
> >
> > i.e urcu-qsbr.h and urcu-bp.h will identical definition of API. The
> > application can simply include ONE header file in a C file based on
> > the flavor.
> > If need both at runtime. Need to have function pointer or so in the
> > application and define the function in different c file by including
> > the approaite flavor in C file.
> 
> This would also be a good time to consider the tradeoffs of the heavy use of
> inlining that is done in rte_ring vs the impact that has on API/ABI stability.
> 
I was working on few requirements in rte_ring library for RCU defer APIs. RFC is at https://patchwork.dpdk.org/cover/66020/. 

  reply	other threads:[~2020-02-24 20:53 UTC|newest]

Thread overview: 146+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 11:35 Konstantin Ananyev
2020-02-24 11:35 ` [dpdk-dev] [RFC 1/6] test/ring: add contention stress test Konstantin Ananyev
2020-02-24 11:35 ` [dpdk-dev] [RFC 2/6] ring: rework ring layout to allow new sync schemes Konstantin Ananyev
2020-02-24 11:35 ` [dpdk-dev] [RFC 3/6] ring: introduce RTS ring mode Konstantin Ananyev
2020-02-24 11:35 ` [dpdk-dev] [RFC 4/6] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-02-24 11:35 ` [dpdk-dev] [RFC 5/6] ring: introduce HTS ring mode Konstantin Ananyev
2020-03-25 20:44   ` Honnappa Nagarahalli
2020-03-26 12:26     ` Ananyev, Konstantin
2020-02-24 11:35 ` [dpdk-dev] [RFC 6/6] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-02-24 16:59 ` [dpdk-dev] [RFC 0/6] New sync modes for ring Stephen Hemminger
2020-02-24 17:59   ` Jerin Jacob
2020-02-24 19:35     ` Stephen Hemminger
2020-02-24 20:52       ` Honnappa Nagarahalli [this message]
2020-02-25 11:45         ` Ananyev, Konstantin
2020-02-25 13:41       ` Ananyev, Konstantin
2020-02-26 16:53         ` Morten Brørup
2020-02-27 10:31         ` Jerin Jacob
2020-02-28  0:17           ` David Christensen
2020-03-20 16:45             ` Ananyev, Konstantin
2020-02-25  0:58     ` Honnappa Nagarahalli
2020-02-25 15:14       ` Ananyev, Konstantin
2020-03-25 20:43 ` Honnappa Nagarahalli
2020-03-26  1:50   ` Ananyev, Konstantin
2020-03-30 21:29     ` Honnappa Nagarahalli
2020-03-30 23:37       ` Honnappa Nagarahalli
2020-03-31 17:21         ` Ananyev, Konstantin
2020-03-31 16:43 ` [dpdk-dev] [PATCH v1 0/8] " Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 1/8] test/ring: add contention stress test Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 2/8] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 3/8] ring: introduce RTS ring mode Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 4/8] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 5/8] ring: introduce HTS ring mode Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 6/8] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 7/8] ring: introduce peek style API Konstantin Ananyev
2020-03-31 16:43   ` [dpdk-dev] [PATCH v1 8/8] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-02 22:09   ` [dpdk-dev] [PATCH v2 0/9] New sync modes for ring Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 1/9] test/ring: add contention stress test Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 2/9] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 3/9] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 4/9] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 5/9] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 6/9] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 7/9] ring: introduce peek style API Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 8/9] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-02 22:09     ` [dpdk-dev] [PATCH v2 9/9] ring: add C11 memory model for new sync modes Konstantin Ananyev
2020-04-03 17:42     ` [dpdk-dev] [PATCH v3 0/9] New sync modes for ring Konstantin Ananyev
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 1/9] test/ring: add contention stress test Konstantin Ananyev
2020-04-08  4:59         ` Honnappa Nagarahalli
2020-04-09 12:36           ` Ananyev, Konstantin
2020-04-09 13:00             ` Ananyev, Konstantin
2020-04-10 18:01               ` Honnappa Nagarahalli
2020-04-10 16:59             ` Honnappa Nagarahalli
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 2/9] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-08  4:59         ` Honnappa Nagarahalli
2020-04-09 13:39           ` Ananyev, Konstantin
2020-04-10 20:15             ` Honnappa Nagarahalli
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 3/9] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-04 17:27         ` Wang, Haiyue
2020-04-08  5:00         ` Honnappa Nagarahalli
2020-04-09 14:52           ` Ananyev, Konstantin
2020-04-10 23:10             ` Honnappa Nagarahalli
2020-04-13 14:29               ` David Marchand
2020-04-13 16:42                 ` Honnappa Nagarahalli
2020-04-14 13:47                   ` David Marchand
2020-04-14 15:57                     ` Honnappa Nagarahalli
2020-04-14 16:21                       ` Ananyev, Konstantin
2020-04-14 13:18               ` Ananyev, Konstantin
2020-04-14 15:58                 ` Honnappa Nagarahalli
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 4/9] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 5/9] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-13 23:27         ` Honnappa Nagarahalli
2020-04-14 16:12           ` Ananyev, Konstantin
2020-04-14 17:06             ` Honnappa Nagarahalli
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 6/9] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 7/9] ring: introduce peek style API Konstantin Ananyev
2020-04-14  3:45         ` Honnappa Nagarahalli
2020-04-14 16:47           ` Ananyev, Konstantin
2020-04-14 17:30             ` Honnappa Nagarahalli
2020-04-14 22:24               ` Ananyev, Konstantin
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 8/9] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-03 17:42       ` [dpdk-dev] [PATCH v3 9/9] ring: add C11 memory model for new sync modes Konstantin Ananyev
2020-04-04 14:16         ` [dpdk-dev] 回复:[PATCH " 周介龙
2020-04-14  4:28         ` [dpdk-dev] [PATCH " Honnappa Nagarahalli
2020-04-14 18:29           ` Ananyev, Konstantin
2020-04-15 20:28           ` Ananyev, Konstantin
2020-04-17 13:36       ` [dpdk-dev] [PATCH v4 0/9] New sync modes for ring Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 1/9] test/ring: add contention stress test Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 2/9] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 3/9] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 4/9] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 5/9] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 6/9] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 7/9] ring: introduce peek style API Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 8/9] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-17 13:36         ` [dpdk-dev] [PATCH v4 9/9] test/ring: add functional tests for new sync modes Konstantin Ananyev
2020-04-18 16:32         ` [dpdk-dev] [PATCH v5 0/9] New sync modes for ring Konstantin Ananyev
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 1/9] test/ring: add contention stress test Konstantin Ananyev
2020-04-19  2:30             ` Honnappa Nagarahalli
2020-04-19  8:03               ` David Marchand
2020-04-19 11:47                 ` Ananyev, Konstantin
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 2/9] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 3/9] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 4/9] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 5/9] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 6/9] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 7/9] ring: introduce peek style API Konstantin Ananyev
2020-04-19  2:31             ` Honnappa Nagarahalli
2020-04-19 18:32               ` Ananyev, Konstantin
2020-04-19 19:12                 ` Ananyev, Konstantin
2020-04-19 21:14                   ` Honnappa Nagarahalli
2020-04-19 22:41                     ` Ananyev, Konstantin
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 8/9] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-19  2:32             ` Honnappa Nagarahalli
2020-04-18 16:32           ` [dpdk-dev] [PATCH v5 9/9] test/ring: add functional tests for new sync modes Konstantin Ananyev
2020-04-19  2:32             ` Honnappa Nagarahalli
2020-04-19  2:32           ` [dpdk-dev] [PATCH v5 0/9] New sync modes for ring Honnappa Nagarahalli
2020-04-20 12:11           ` [dpdk-dev] [PATCH v6 00/10] " Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 01/10] test/ring: add contention stress test Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 02/10] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 03/10] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 04/10] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 05/10] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 06/10] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 07/10] ring: introduce peek style API Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 08/10] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 09/10] test/ring: add functional tests for new sync modes Konstantin Ananyev
2020-04-20 12:11             ` [dpdk-dev] [PATCH v6 10/10] doc: update ring guide Konstantin Ananyev
2020-04-20 13:47               ` David Marchand
2020-04-20 14:07                 ` Ananyev, Konstantin
2020-04-20 12:28             ` [dpdk-dev] [PATCH v7 00/10] New sync modes for ring Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 01/10] test/ring: add contention stress test Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 02/10] ring: prepare ring to allow new sync schemes Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 03/10] ring: introduce RTS ring mode Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 04/10] test/ring: add contention stress test for RTS ring Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 05/10] ring: introduce HTS ring mode Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 06/10] test/ring: add contention stress test for HTS ring Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 07/10] ring: introduce peek style API Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 08/10] test/ring: add stress test for MT peek API Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 09/10] test/ring: add functional tests for new sync modes Konstantin Ananyev
2020-04-20 12:28               ` [dpdk-dev] [PATCH v7 10/10] doc: update ring guide Konstantin Ananyev
2020-04-21 11:31               ` [dpdk-dev] [PATCH v7 00/10] New sync modes for ring David Marchand

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