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From: Jia He <hejianet@gmail.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	"Zhao, Bing" <ilovethull@163.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>,
	"Richardson, Bruce" <bruce.richardson@intel.com>,
	jianbo.liu@arm.com, hemant.agrawal@nxp.com
Subject: Re: [dpdk-dev] [PATCH] ring: guarantee ordering of cons/prod loading when doing enqueue/dequeue
Date: Fri, 3 Nov 2017 10:55:40 +0800	[thread overview]
Message-ID: <fc05d426-a48a-4887-7365-85822d3996ac@gmail.com> (raw)
In-Reply-To: <8bc4095d-301e-3e99-9644-27848d97e9bc@gmail.com>

Hi Jerin


On 11/2/2017 4:57 PM, Jia He Wrote:
>
> Hi, Jerin
> please see my performance test below
> On 11/2/2017 3:04 AM, Jerin Jacob Wrote:
> [...]
>> Should it be like instead?
>>
>> +#else
>> +        *old_head = __atomic_load_n(&r->cons.head, __ATOMIC_ACQUIRE);
>> +        const uint32_t prod_tail = __atomic_load_n(&r->prod.tail,
>> __ATOMIC_ACQUIRE);
>> It would be nice to see how much overhead it gives.ie back to back
>> __ATOMIC_ACQUIRE.
> I can NOT test ring_perf_autotest in our server because of the 
> something wrong in PMU counter.
> All the return value of rte_rdtsc is 0 with and without your provided 
> ko module. I am still
> investigating the reason.
>

Hi Jerin

As for the root cause of rte_rdtsc issue, it might be due to the pmu 
counter frequency is too low

in our arm64 server("Amberwing" from qualcom)

[586990.057779] arch_timer_get_cntfrq()=20000000

Only 20MHz instead of 100M/200MHz, and CNTFRQ_EL0 is not even writable 
in kernel space.

Maybe the code in ring_perf_autotest needs to be changed?

e.g.

     printf("SC empty dequeue: %.2F\n",
             (double)(sc_end-sc_start) / iterations);
     printf("MC empty dequeue: %.2F\n",
             (double)(mc_end-mc_start) / iterations);

Otherwise it is always 0 if the time difference divides by iterations.


-- 
Cheers,
Jia

  reply	other threads:[~2017-11-03  2:55 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
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 [this message]
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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