[dpdk-dev] [PATCH] ring: guarantee ordering of cons/prod loading when doing enqueue/dequeue
jerin.jacob at caviumnetworks.com
Fri Oct 13 03:49:16 CEST 2017
> Date: Fri, 13 Oct 2017 09:16:31 +0800
> From: Jia He <hejianet at gmail.com>
> To: Jerin Jacob <jerin.jacob at caviumnetworks.com>, "Ananyev, Konstantin"
> <konstantin.ananyev at intel.com>
> Cc: Olivier MATZ <olivier.matz at 6wind.com>, "dev at dpdk.org" <dev at dpdk.org>,
> "jia.he at hxt-semitech.com" <jia.he at hxt-semitech.com>,
> "jie2.liu at hxt-semitech.com" <jie2.liu at hxt-semitech.com>,
> "bing.zhao at hxt-semitech.com" <bing.zhao at 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
> 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 ;-)
> 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
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
I will also spend on cycles on this.
> > 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
More information about the dev