From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id DAA2EC5A0 for ; Thu, 16 Jun 2016 10:55:50 +0200 (CEST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 16 Jun 2016 01:55:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,478,1459839600"; d="scan'208";a="976870241" Received: from dhunt5-mobl.ger.corp.intel.com (HELO [10.237.220.29]) ([10.237.220.29]) by orsmga001.jf.intel.com with ESMTP; 16 Jun 2016 01:55:48 -0700 To: Olivier MATZ , Jan Viktorin References: <1465919341-3209-1-git-send-email-david.hunt@intel.com> <1465976824-83823-1-git-send-email-david.hunt@intel.com> <20160615121358.5ef9f142@pcviktorin.fit.vutbr.cz> <57614043.9090603@intel.com> <57614402.6020708@6wind.com> <576183AD.8070200@intel.com> <576184F7.3040206@6wind.com> <576259A2.4090200@intel.com> <57626787.6090709@6wind.com> Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, shreyansh.jain@nxp.com From: "Hunt, David" Message-ID: <57626992.9020009@intel.com> Date: Thu, 16 Jun 2016 09:55:46 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <57626787.6090709@6wind.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v12 0/3] mempool: add external mempool manager X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Jun 2016 08:55:51 -0000 On 16/6/2016 9:47 AM, Olivier MATZ wrote: > > > On 06/16/2016 09:47 AM, Hunt, David wrote: >> >> >> On 15/6/2016 5:40 PM, Olivier MATZ wrote: >>> >>> >>> On 06/15/2016 06:34 PM, Hunt, David wrote: >>>> >>>> >>>> On 15/6/2016 1:03 PM, Olivier MATZ wrote: >>>>> [...] >>>>> >>>>> The opaque pointer would be saved in mempool structure, and used >>>>> when the mempool is populated (calling mempool_ops_alloc). >>>>> The type of the structure pointed by the opaque has to be defined >>>>> (and documented) into each mempool_ops manager. >>>>> >>>>> >>>>> Olivier >>>> >>>> >>>> OK, just to be sure before I post another patchset..... >>>> >>>> For the rte_mempool_struct: >>>> struct rte_mempool_memhdr_list mem_list; /**< List of memory >>>> chunks */ >>>> + void *ops_args; /**< optional args for ops >>>> alloc. */ >>>> >>>> (at the end of the struct, as it's just on the control path, not to >>>> affect fast path) >>> >>> Hmm, I would put it just after pool_data. >>> >> >> When I move it to just after pool data, the performance of the >> mempool_perf_autotest drops by 2% on my machine for the local cache >> tests. >> I think I should leave it where I suggested. > > I don't really see what you call control path and data path here. > For me, all the fields in mempool structure are not modified once > the mempool is initialized. > > http://dpdk.org/browse/dpdk/tree/lib/librte_mempool/rte_mempool.h?id=ce94a51ff05c0a4b63177f8a314feb5d19992036#n201 > > > So I don't think we should have more cache misses whether it's > placed at the beginning or at the end. Maybe I'm missing something... > > I still believe it's better to group the 2 fields as they are > tightly linked together. It could be at the end if you see better > performance. > OK, I'll leave at the end because of the performance hit. Regards, David.