From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo2.mail-out.ovh.net (7.mo2.mail-out.ovh.net [188.165.48.182]) by dpdk.org (Postfix) with ESMTP id 3FF9F156 for ; Wed, 4 Dec 2013 21:03:12 +0100 (CET) Received: from mail422.ha.ovh.net (gw6.ovh.net [213.251.189.206]) by mo2.mail-out.ovh.net (Postfix) with SMTP id 5DA5EFF8FE5 for ; Wed, 4 Dec 2013 21:04:09 +0100 (CET) Received: from b0.ovh.net (HELO queueout) (213.186.33.50) by b0.ovh.net with SMTP; 4 Dec 2013 22:04:16 +0200 Received: from lneuilly-152-23-9-75.w193-252.abo.wanadoo.fr (HELO pcdeff) (ff@ozog.com@193.252.40.75) by ns0.ovh.net with SMTP; 4 Dec 2013 22:04:15 +0200 From: =?iso-8859-1?Q?Fran=E7ois-Fr=E9d=E9ric_Ozog?= To: "'Sambath Kumar Balasubramanian'" References: <03b201cef0f7$5fba0d20$1f2e2760$@com> In-Reply-To: Date: Wed, 4 Dec 2013 21:02:32 +0100 Message-ID: <03ee01cef12b$c56d85a0$504890e0$@com> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Ac7w+TP8edKMNaA/S+SOl/dYvD/G7AAMZoEg Content-Language: fr X-Ovh-Tracer-Id: 9997709698291783897 X-Ovh-Remote: 193.252.40.75 (lneuilly-152-23-9-75.w193-252.abo.wanadoo.fr) X-Ovh-Local: 213.186.33.20 (ns0.ovh.net) X-OVH-SPAMSTATE: OK X-OVH-SPAMSCORE: -100 X-OVH-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeiledrkeeiucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd X-Spam-Check: DONE|U 0.5/N X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeiledrkeeiucetufdoteggodetrfcurfhrohhfihhlvgemucfqggfjnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: dev@dpdk.org Subject: Re: [dpdk-dev] Question on the Ring Library 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, 04 Dec 2013 20:03:12 -0000 You are welcome ! =20 Even if you insert packets in batch into a fifo, the mutex is still unpredictable. If one pthread_lock costs 1ms, you are going to lose = packets, regardless of the number of RSS queues and ring sizes=85 Batching comes = with another issue: need to flush a batch after a certain timeout if you do = not have packets. Userland timer resolution is such that you are introducing port to port latency quite a lot: DPDK native, you can manage to get a = 2=B5s latency (including PCI express), while with batch it may be 1ms=85 You = may find smarter algorithms but still you will be an order of magnitude = higher than DPDK. =20 Hope this helps. =20 Fran=E7ois-Fr=E9d=E9ric =20 De : Sambath Kumar Balasubramanian [mailto:sambath.balasubramanian@gmail.com]=20 Envoy=E9 : mercredi 4 d=E9cembre 2013 15:01 =C0 : Fran=E7ois-Fr=E9d=E9ric Ozog Cc : dev@dpdk.org Objet : Re: [dpdk-dev] Question on the Ring Library =20 Thanks Fran=E7ois-Fr=E9d=E9ric. That puts real good perspective on the = cost for the vent assuming each packet in the fast will result in an event. If event rate is orders of magnitude less than the packet = rate, then I guess we can still achieve 10G since the "extra cost" will be in = the event thread and not in the fast path thread. =20 Regards, Sambath