From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jia He Subject: Re: [PATCH] ring: guarantee ordering of cons/prod loading when doing enqueue/dequeue Date: Thu, 2 Nov 2017 16:57:06 +0800 Message-ID: <8bc4095d-301e-3e99-9644-27848d97e9bc@gmail.com> References: <2601191342CEEE43887BDE71AB9772585FAAB570@IRSMSX103.ger.corp.intel.com> <3e580cd7-2854-d855-be9c-7c4ce06e3ed5@gmail.com> <20171020054319.GA4249@jerin> <20171023100617.GA17957@jerin> <20171025132642.GA13977@jerin> <20171031111433.GA21742@jerin> <69adfb00-4582-b362-0540-d1d9d6bcf6aa@gmail.com> <20171101190420.GA21407@jerin> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: "Ananyev, Konstantin" , "Zhao, Bing" , Olivier MATZ , "dev@dpdk.org" , "jia.he@hxt-semitech.com" , "jie2.liu@hxt-semitech.com" , "bing.zhao@hxt-semitech.com" , "Richardson, Bruce" , jianbo.liu@arm.com, hemant.agrawal@nxp.com To: Jerin Jacob Return-path: Received: from mail-io0-f170.google.com (mail-io0-f170.google.com [209.85.223.170]) by dpdk.org (Postfix) with ESMTP id C3B96271 for ; Thu, 2 Nov 2017 09:57:28 +0100 (CET) Received: by mail-io0-f170.google.com with SMTP id i38so12261983iod.2 for ; Thu, 02 Nov 2017 01:57:28 -0700 (PDT) In-Reply-To: <20171101190420.GA21407@jerin> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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.  I ever tested the difference with my debug patch, the difference is minor, less than +-1% -- Cheers, Jia > >> >> Cheers, >> >> Jia >> >> >> >> On 10/31/2017 7:14 PM, Jerin Jacob Wrote: >>> -----Original Message----- >>>> Date: Tue, 31 Oct 2017 10:55:15 +0800 >>>> From: Jia He >>>> To: Jerin Jacob >>>> Cc: "Ananyev, Konstantin" , "Zhao, Bing" >>>> , Olivier MATZ , >>>> "dev@dpdk.org" , "jia.he@hxt-semitech.com" >>>> , "jie2.liu@hxt-semitech.com" >>>> , "bing.zhao@hxt-semitech.com" >>>> , "Richardson, Bruce" >>>> >>>> Subject: Re: [dpdk-dev] [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/52.4.0 >>>> >>>> Hi Jerin >>> Hi Jia, >>> >>>> Do you think  next step whether I need to implement the load_acquire half >>>> barrier as per freebsd >>> I did a quick prototype using C11 memory model(ACQUIRE/RELEASE) schematics >>> and tested on two arm64 platform in Cavium(Platform A: Non arm64 OOO machine) >>> and Platform B: arm64 OOO machine) >>> >>> smp_rmb() performs better in Platform A: >>> acquire/release semantics perform better in platform B: >>> >>> Here is the patch: >>> https://github.com/jerinjacobk/mytests/blob/master/ring/0001-ring-using-c11-memory-model.patch >>> >>> In terms of next step: >>> - I am not sure the cost associated with acquire/release semantics on x86 or ppc. >>> IMO, We need to have both options under conditional compilation >>> flags and let the target platform choose the best one. >>> >>> Thoughts? >>> >>> Here is the performance numbers: >>> - Both platforms are running at different frequency, So absolute numbers does not >>> matter, Just check the relative numbers. >>> >>> Platform A: Performance numbers: >>> ================================ >>> no patch(Non arm64 OOO machine) >>> ------------------------------- >>> >>> SP/SC single enq/dequeue: 40 >>> MP/MC single enq/dequeue: 282 >>> SP/SC burst enq/dequeue (size: 8): 11 >>> MP/MC burst enq/dequeue (size: 8): 42 >>> SP/SC burst enq/dequeue (size: 32): 8 >>> MP/MC burst enq/dequeue (size: 32): 16 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 8.01 >>> MC empty dequeue: 11.01 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 11.30 >>> MP/MC bulk enq/dequeue (size: 8): 42.85 >>> SP/SC bulk enq/dequeue (size: 32): 8.25 >>> MP/MC bulk enq/dequeue (size: 32): 16.46 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 20.62 >>> MP/MC bulk enq/dequeue (size: 8): 56.30 >>> SP/SC bulk enq/dequeue (size: 32): 10.94 >>> MP/MC bulk enq/dequeue (size: 32): 18.66 >>> Test OK >>> >>> # smp_rmb() patch((Non OOO arm64 machine) >>> http://dpdk.org/dev/patchwork/patch/30029/ >>> ----------------------------------------- >>> >>> SP/SC single enq/dequeue: 42 >>> MP/MC single enq/dequeue: 291 >>> SP/SC burst enq/dequeue (size: 8): 12 >>> MP/MC burst enq/dequeue (size: 8): 44 >>> SP/SC burst enq/dequeue (size: 32): 8 >>> MP/MC burst enq/dequeue (size: 32): 16 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 13.01 >>> MC empty dequeue: 15.01 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 11.60 >>> MP/MC bulk enq/dequeue (size: 8): 44.32 >>> SP/SC bulk enq/dequeue (size: 32): 8.60 >>> MP/MC bulk enq/dequeue (size: 32): 16.50 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 20.95 >>> MP/MC bulk enq/dequeue (size: 8): 56.90 >>> SP/SC bulk enq/dequeue (size: 32): 10.90 >>> MP/MC bulk enq/dequeue (size: 32): 18.78 >>> Test OK >>> RTE>> >>> >>> # c11 memory model patch((Non OOO arm64 machine) >>> https://github.com/jerinjacobk/mytests/blob/master/ring/0001-ring-using-c11-memory-model.patch >>> --------------------------------------------------------------------------------------------- >>> ### Testing single element and burst enq/deq ### >>> SP/SC single enq/dequeue: 197 >>> MP/MC single enq/dequeue: 328 >>> SP/SC burst enq/dequeue (size: 8): 31 >>> MP/MC burst enq/dequeue (size: 8): 50 >>> SP/SC burst enq/dequeue (size: 32): 13 >>> MP/MC burst enq/dequeue (size: 32): 18 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 13.01 >>> MC empty dequeue: 18.02 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 30.95 >>> MP/MC bulk enq/dequeue (size: 8): 50.30 >>> SP/SC bulk enq/dequeue (size: 32): 13.27 >>> MP/MC bulk enq/dequeue (size: 32): 18.11 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 43.38 >>> MP/MC bulk enq/dequeue (size: 8): 64.42 >>> SP/SC bulk enq/dequeue (size: 32): 16.71 >>> MP/MC bulk enq/dequeue (size: 32): 22.21 >>> >>> >>> Platform B: Performance numbers: >>> ============================== >>> #no patch(OOO arm64 machine) >>> ---------------------------- >>> >>> ### Testing single element and burst enq/deq ### >>> SP/SC single enq/dequeue: 81 >>> MP/MC single enq/dequeue: 207 >>> SP/SC burst enq/dequeue (size: 8): 15 >>> MP/MC burst enq/dequeue (size: 8): 31 >>> SP/SC burst enq/dequeue (size: 32): 7 >>> MP/MC burst enq/dequeue (size: 32): 11 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 3.00 >>> MC empty dequeue: 5.00 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 15.38 >>> MP/MC bulk enq/dequeue (size: 8): 30.64 >>> SP/SC bulk enq/dequeue (size: 32): 7.25 >>> MP/MC bulk enq/dequeue (size: 32): 11.06 >>> >>> ### Testing using two hyperthreads ### >>> SP/SC bulk enq/dequeue (size: 8): 31.51 >>> MP/MC bulk enq/dequeue (size: 8): 49.38 >>> SP/SC bulk enq/dequeue (size: 32): 14.32 >>> MP/MC bulk enq/dequeue (size: 32): 15.89 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 72.66 >>> MP/MC bulk enq/dequeue (size: 8): 121.89 >>> SP/SC bulk enq/dequeue (size: 32): 16.88 >>> MP/MC bulk enq/dequeue (size: 32): 24.23 >>> Test OK >>> RTE>> >>> >>> >>> # smp_rmb() patch((OOO arm64 machine) >>> http://dpdk.org/dev/patchwork/patch/30029/ >>> ------------------------------------------- >>> >>> ### Testing single element and burst enq/deq ### >>> SP/SC single enq/dequeue: 152 >>> MP/MC single enq/dequeue: 265 >>> SP/SC burst enq/dequeue (size: 8): 24 >>> MP/MC burst enq/dequeue (size: 8): 39 >>> SP/SC burst enq/dequeue (size: 32): 9 >>> MP/MC burst enq/dequeue (size: 32): 13 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 31.01 >>> MC empty dequeue: 32.01 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 24.26 >>> MP/MC bulk enq/dequeue (size: 8): 39.52 >>> SP/SC bulk enq/dequeue (size: 32): 9.47 >>> MP/MC bulk enq/dequeue (size: 32): 13.31 >>> >>> ### Testing using two hyperthreads ### >>> SP/SC bulk enq/dequeue (size: 8): 40.29 >>> MP/MC bulk enq/dequeue (size: 8): 59.57 >>> SP/SC bulk enq/dequeue (size: 32): 17.34 >>> MP/MC bulk enq/dequeue (size: 32): 21.58 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 79.05 >>> MP/MC bulk enq/dequeue (size: 8): 153.46 >>> SP/SC bulk enq/dequeue (size: 32): 26.41 >>> MP/MC bulk enq/dequeue (size: 32): 38.37 >>> Test OK >>> RTE>> >>> >>> >>> # c11 memory model patch((OOO arm64 machine) >>> https://github.com/jerinjacobk/mytests/blob/master/ring/0001-ring-using-c11-memory-model.patch >>> ---------------------------------------------------------------------------------------------- >>> ### Testing single element and burst enq/deq ### >>> SP/SC single enq/dequeue: 98 >>> MP/MC single enq/dequeue: 130 >>> SP/SC burst enq/dequeue (size: 8): 18 >>> MP/MC burst enq/dequeue (size: 8): 22 >>> SP/SC burst enq/dequeue (size: 32): 7 >>> MP/MC burst enq/dequeue (size: 32): 9 >>> >>> ### Testing empty dequeue ### >>> SC empty dequeue: 4.00 >>> MC empty dequeue: 5.00 >>> >>> ### Testing using a single lcore ### >>> SP/SC bulk enq/dequeue (size: 8): 17.40 >>> MP/MC bulk enq/dequeue (size: 8): 22.88 >>> SP/SC bulk enq/dequeue (size: 32): 7.62 >>> MP/MC bulk enq/dequeue (size: 32): 8.96 >>> >>> ### Testing using two hyperthreads ### >>> SP/SC bulk enq/dequeue (size: 8): 20.24 >>> MP/MC bulk enq/dequeue (size: 8): 25.83 >>> SP/SC bulk enq/dequeue (size: 32): 12.21 >>> MP/MC bulk enq/dequeue (size: 32): 13.20 >>> >>> ### Testing using two physical cores ### >>> SP/SC bulk enq/dequeue (size: 8): 67.54 >>> MP/MC bulk enq/dequeue (size: 8): 124.63 >>> SP/SC bulk enq/dequeue (size: 32): 21.13 >>> MP/MC bulk enq/dequeue (size: 32): 28.44 >>> Test OK >>> RTE>>quit >>> >>> >>>> or find any other performance test case to compare the performance impact? >>> As far as I know, ring_perf_autotest is the better performance test. >>> If you have trouble in using "High-resolution cycle counter" in your platform then also >>> you can use ring_perf_auto test to compare the performance(as relative >>> number matters) >>> >>> Jerin >>> >>>> Thanks for any suggestions. >>>> >>>> Cheers, >>>> Jia