From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Jia He <hejianet@gmail.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Olivier MATZ <olivier.matz@6wind.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"jia.he@hxt-semitech.com" <jia.he@hxt-semitech.com>,
"jie2.liu@hxt-semitech.com" <jie2.liu@hxt-semitech.com>,
"bing.zhao@hxt-semitech.com" <bing.zhao@hxt-semitech.com>
Subject: Re: [dpdk-dev] [PATCH] ring: guarantee ordering of cons/prod loading when doing enqueue/dequeue
Date: Fri, 13 Oct 2017 07:19:16 +0530 [thread overview]
Message-ID: <20171013014914.GA2067@jerin> (raw)
In-Reply-To: <d48351a5-2c43-4fff-0a66-fd06707a530d@gmail.com>
-----Original Message-----
> Date: Fri, 13 Oct 2017 09:16:31 +0800
> From: Jia He <hejianet@gmail.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, "Ananyev, Konstantin"
> <konstantin.ananyev@intel.com>
> Cc: Olivier MATZ <olivier.matz@6wind.com>, "dev@dpdk.org" <dev@dpdk.org>,
> "jia.he@hxt-semitech.com" <jia.he@hxt-semitech.com>,
> "jie2.liu@hxt-semitech.com" <jie2.liu@hxt-semitech.com>,
> "bing.zhao@hxt-semitech.com" <bing.zhao@hxt-semitech.com>
> Subject: Re: [PATCH] ring: guarantee ordering of cons/prod loading when
> doing enqueue/dequeue
> User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
> Thunderbird/52.3.0
>
> Hi
>
>
> On 10/13/2017 9:02 AM, Jia He Wrote:
> > Hi Jerin
> >
> >
> > On 10/13/2017 1:23 AM, Jerin Jacob Wrote:
> > > -----Original Message-----
> > > > Date: Thu, 12 Oct 2017 17:05:50 +0000
> > > >
> [...]
> > > On the same lines,
> > >
> > > Jia He, jie2.liu, bing.zhao,
> > >
> > > Is this patch based on code review or do you saw this issue on any
> > > of the
> > > arm/ppc target? arm64 will have performance impact with this change.
> sorry, miss one important information
> Our platform is an aarch64 server with 46 cpus.
Is this an OOO(Out of order execution) aarch64 CPU implementation?
> If we reduced the involved cpu numbers, the bug occurred less frequently.
>
> Yes, mb barrier impact the performance, but correctness is more important,
> isn't it ;-)
Yes.
> Maybe we can find any other lightweight barrier here?
Yes, Regarding the lightweight barrier, arm64 has native support for acquire and release
semantics, which is exposed through gcc as architecture agnostic
functions.
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
http://preshing.com/20130922/acquire-and-release-fences/
Good to know,
1) How much overhead this patch in your platform? Just relative
numbers are enough
2) As a prototype, Is Changing to acquire and release schematics
reduces the overhead in your platform?
Reference FreeBSD ring/DPDK style ring implementation through acquire
and release schematics
https://github.com/Linaro/odp/blob/master/platform/linux-generic/pktio/ring.c
I will also spend on cycles on this.
>
> Cheers,
> Jia
> > Based on mbuf_autotest, the rte_panic will be invoked in seconds.
> >
> > PANIC in test_refcnt_iter():
> > (lcore=0, iter=0): after 10s only 61 of 64 mbufs left free
> > 1: [./test(rte_dump_stack+0x38) [0x58d868]]
> > Aborted (core dumped)
> >
> > Cheers,
> > Jia
> > >
> > >
> > > > Konstantin
> >
>
next prev parent reply other threads:[~2017-10-13 1:49 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-10 9:56 Jia He
2017-10-12 15:53 ` Olivier MATZ
2017-10-12 16:15 ` Stephen Hemminger
2017-10-12 17:05 ` Ananyev, Konstantin
2017-10-12 17:23 ` Jerin Jacob
2017-10-13 1:02 ` Jia He
2017-10-13 1:15 ` Jia He
2017-10-13 1:16 ` Jia He
2017-10-13 1:49 ` Jerin Jacob [this message]
2017-10-13 3:23 ` Jia He
2017-10-13 5:57 ` Zhao, Bing
2017-10-13 7:33 ` Jianbo Liu
2017-10-13 8:20 ` Jia He
2017-10-19 10:02 ` Ananyev, Konstantin
2017-10-19 11:18 ` Zhao, Bing
2017-10-19 14:15 ` Ananyev, Konstantin
2017-10-19 20:02 ` Ananyev, Konstantin
2017-10-20 1:57 ` Jia He
2017-10-20 5:43 ` Jerin Jacob
2017-10-23 8:49 ` Jia He
2017-10-23 9:05 ` Kuusisaari, Juhamatti
2017-10-23 9:10 ` Bruce Richardson
2017-10-23 10:06 ` Jerin Jacob
2017-10-24 2:04 ` Jia He
2017-10-25 13:26 ` Jerin Jacob
2017-10-26 2:27 ` Jia He
2017-10-31 2:55 ` Jia He
2017-10-31 11:14 ` Jerin Jacob
2017-11-01 2:53 ` Jia He
2017-11-01 19:04 ` Jerin Jacob
2017-11-02 1:09 ` Jia He
2017-11-02 8:57 ` Jia He
2017-11-03 2:55 ` Jia He
2017-11-03 12:47 ` Jerin Jacob
2017-11-01 4:48 ` Jia He
2017-11-01 19:10 ` Jerin Jacob
2017-10-20 7:03 ` Ananyev, Konstantin
2017-10-13 0:24 ` Liu, Jie2
2017-10-13 2:12 ` Zhao, Bing
2017-10-13 2:34 ` Jerin Jacob
2017-10-16 10:51 ` Kuusisaari, Juhamatti
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