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charset=GBK Content-Transfer-Encoding: base64 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] lpm performance 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: Wed, 21 Sep 2016 02:42:52 -0000 R290IGl0LiAgVGhhbmtzIGZvciB5b3VyIGd1aWRhbmNlISAKCgoKCgoKCgrU2iAyMDE2LTA5LTIw IDIyOjQxOjM2o6wiQW5kcml5IEJlcmVzdG92c2t5eSIgPGFiZXJAc2VtaWhhbGYuY29tPiDQtLXA o7oKPkFGQUlSIEludGVsIGhhcmR3YXJlIHNob3VsZCBkbyB0aGUgMTBHYml0L3MgbGluZSByYXRl IChpLmUuIH4xNCw4Cj5NUFBTKSB3aXRoIG9uZSBmbG93IGFuZCBMUE0gcXVpdGUgZWFzaWx5LiBT b3JyeSwgSSBkb24ndCBoYXZlIG51bWJlcnMKPnRvIHNoYXJlIGF0IGhhbmQuCj4KPlJlZ2FyZGlu ZyB0aGUgdG9vbCBwbGVhc2Ugc2VlIHRoZSBwa3RnZW4tZHBkayBvciBUUmV4LiBSZWdhcmRpbmcg dGhlCj5udW1iZXIgb2YgZmxvd3MgYW5kIG92ZXJhbGwgYmVuY2htYXJraW5nIG1ldGhvZG9sb2d5 IC0gcGxlYXNlIHNlZQo+UkZDMjU0NC4KPgo+QW5kcml5Cj4KPgo+T24gVHVlLCBTZXAgMjAsIDIw MTYgYXQgMTI6NDcgUE0sINXFzrAgPHpoYW5nd3FoQDEyNi5jb20+IHdyb3RlOgo+PiBUaGFua3Mg c28gbXVjaCBmb3IgeW91ciByZXBseSEgIFVzdWFsbHkgaG93IGRpZCB5b3UgdGVzdCBscG0gcGVy Zm9ybWFuY2UKPj4gd2l0aCB2YXJpZXR5IG9mIGRlc3RpbmF0aW9uIGFkZHJlc3Nlcz8gdXNlIHdo aWNoIHRvb2wgc2VuZCB0aGUgdHJhZmZpYz8gaG93Cj4+IG1hbnkgZmxvd3MgcnVsZXMgd2lsbCB5 b3UgYWRkPyB3aGF0J3MgdGhlIHBlcmZvcm1hbmNlIHlvdSBnZXQ/Cj4+Cj4+Cj4+Cj4+Cj4+Cj4+ Cj4+IEF0IDIwMTYtMDktMjAgMTc6NDE6MTMsICJBbmRyaXkgQmVyZXN0b3Zza3l5IiA8YWJlckBz ZW1paGFsZi5jb20+IHdyb3RlOgo+Pj5IZXksCj4+PllvdSBhcmUgY29ycmVjdC4gVGhlIExQTSBt aWdodCBuZWVkIGp1c3Qgb25lIChUQkwyNCkgb3IgdHdvIG1lbW9yeQo+Pj5yZWFkcyAoVEJMMjQg KyBUQkw4KS4gVGhlIHBlcmZvcm1hbmNlIGFsc28gZHJvcHMgb25jZSB5b3UgaGF2ZSBhCj4+PnZh cmlldHkgb2YgZGVzdGluYXRpb24gYWRkcmVzc2VzIGluc3RlYWQgb2YganVzdCBvbmUgKGNhY2hl IG1pc3NlcykuCj4+Pgo+Pj5JbiB5b3VyIGNhc2UgZm9yIHRoZSBkc3QgSVAgMTkyLjE2OC4xLjIg eW91IHdpbGwgaGF2ZSB0d28gbWVtb3J5IHJlYWRzCj4+PihUQkwyNCArIFRCTDgpLCBiZWNhdXNl IDE5Mi4xNjguMS8yNCBibG9jayBoYXMgdGhlIG1vcmUgc3BlY2lmaWMgcm91dGUKPj4+MTkyLjE2 OC4xLjEvMzIuCj4+Pgo+Pj5SZWdhcmRzLAo+Pj5BbmRyaXkKPj4+Cj4+Pk9uIFR1ZSwgU2VwIDIw LCAyMDE2IGF0IDEyOjE4IEFNLCDVxc6wIDx6aGFuZ3dxaEAxMjYuY29tPiB3cm90ZToKPj4+PiBI aSBhbGwsCj4+Pj4KPj4+Pgo+Pj4+IERvZXMgYW55b25lIHRlc3QgSVB2NCBwZXJmb3JtYW5jZT8g SWYgc28sIHdoYXQncyB0aGUgdGhyb3VnaHB1dD8gSSBjYW4KPj4+PiBnZXQgYWxtb3N0IDEwR2Ig d2l0aCA2NCBieXRlIHBhY2tldHMuICBCdXQgYmVmb3JlIHRoZSB0ZXN0LCBJIHdvdWxkIGV4cGVj dAo+Pj4+IGl0IHdpbGwgYmUgbGVzcyB0aGFuIDEwRy4gIEkgdGhvdWdodCB0aGUgcGVyZm9ybWFu Y2Ugd2lsbCBub3QgYmUgYWZmZWN0ZWQgYnkKPj4+PiB0aGUgIG51bWJlciBvZiBydWxlIGVudGly ZXMuIEJ1dCB0aGUgdGhyb3VnaHB1dCB3aWxsIGJlIHJlbGF0ZWQgdG8gd2hldGhlcgo+Pj4+IHRo ZSBmbG93IG5lZWRzIHRvIGNoZWNrIHRoZSBzZWNvbmQgbGF5ZXIgdGFibGUgOiBUQkw4LiAgSXMg bXkgdW5kZXJzdGFuZGluZwo+Pj4+IGNvcnJlY3Q/IEkgYWRkZWQgdGhpcyBmbG93IGVudHJpZXMg Zm9sbG93aW5nIHRoaXMgbGluazoKPj4+PiBodHRwOi8vd3d3LnNsaWRlc2hhcmUubmV0L2dhcnlh Y2h5L3VuZGVyc3RhbmRpbmctZGRwZC1hbGdvcml0aG1pY3MKPj4+PiBzbGlkZSAxMCwKPj4+Pgo+ Pj4+Cj4+Pj4KPj4+PiBzdHJ1Y3QgaXB2NF9scG1fcm91dGUgaXB2NF9scG1fcm91dGVfYXJyYXlb XSA9IHsKPj4+Pgo+Pj4+ICAgICAgICAge0lQdjQoMTkyLCAxNjgsIDAsIDApLCAxNiwgMH0sCj4+ Pj4KPj4+PiAgICAgICAgIHtJUHY0KDE5MiwgMTY4LCAxLCAwKSwgMjQsIDF9LAo+Pj4+Cj4+Pj4g ICAgICAgICB7SVB2NCgxOTIsIDE2OCwgMSwgMSksIDMyLCAyfQo+Pj4+Cj4+Pj4gfTsKPj4+Pgo+ Pj4+IHNlbmQgdGhlIGZsb3cgd2l0aCBkc3QgSVA6Cj4+Pj4KPj4+PiAxOTIuMTY4LjEuMgo+Pj4+ Cj4+Pj4gSXQgc2hvdWxkIGNoZWNrIHRoZSBzZWNvbmQgbGF5ZXIgdGFibGUuIEJ1dCB0aGUgcGVy Zm9ybWFuY2UgaXMgc3RpbGwgMTBHLgo+Pj4+IERvZXMgYW55IHBhcnQgZ28gd3Jvbmcgd2l0aCBt eSBzZXR1cD8gT3IgaXQgcmVhbGx5IGNhbiBhY2hpZXZlIDEwRyB3aXRoIDY0Cj4+Pj4gYnl0ZSBw YWNrZXQgc2l6ZS4KPj4+Pgo+Pj4+IFRoYW5rcywKPj4+Pgo+Pj4+Cj4+Pgo+Pj4KPj4+Cj4+Pi0t Cj4+PkFuZHJpeSBCZXJlc3RvdnNreXkKPj4KPj4KPj4KPj4KPgo+Cj4KPi0tIAo+QW5kcml5IEJl cmVzdG92c2t5eQo= >From maxime.coquelin@redhat.com Wed Sep 21 06:33:00 2016 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id D9F062B84 for ; Wed, 21 Sep 2016 06:32:59 +0200 (CEST) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6B881C0567B2; Wed, 21 Sep 2016 04:32:58 +0000 (UTC) Received: from [10.36.6.63] (vpn1-6-63.ams2.redhat.com [10.36.6.63]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8L4WsQd000878 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 21 Sep 2016 00:32:56 -0400 To: Zhihong Wang , dev@dpdk.org References: <1471319402-112998-1-git-send-email-zhihong.wang@intel.com> <1474336817-22683-1-git-send-email-zhihong.wang@intel.com> <1474336817-22683-7-git-send-email-zhihong.wang@intel.com> Cc: yuanhan.liu@linux.intel.com, thomas.monjalon@6wind.com From: Maxime Coquelin Message-ID: <2482b769-c5db-95a4-be52-18b444f75dfb@redhat.com> Date: Wed, 21 Sep 2016 06:32:54 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1474336817-22683-7-git-send-email-zhihong.wang@intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 21 Sep 2016 04:32:58 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v6 6/6] vhost: optimize cache access 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: Wed, 21 Sep 2016 04:33:00 -0000 On 09/20/2016 04:00 AM, Zhihong Wang wrote: > This patch reorders the code to delay virtio header write to improve > cache access efficiency for cases where the mrg_rxbuf feature is turned > on. CPU pipeline stall cycles can be significantly reduced. > > Virtio header write and mbuf data copy are all remote store operations > which takes a long time to finish. It's a good idea to put them together > to remove bubbles in between, to let as many remote store instructions > as possible go into store buffer at the same time to hide latency, and > to let the H/W prefetcher goes to work as early as possible. > > On a Haswell machine, about 100 cycles can be saved per packet by this > patch alone. Taking 64B packets traffic for example, this means about 60% > efficiency improvement for the enqueue operation. Thanks for the detailed information, I appreciate it. Maxime