Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756582Ab3FEPrW (ORCPT ); Wed, 5 Jun 2013 11:47:22 -0400 Received: from mga09.intel.com ([134.134.136.24]:18006 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753913Ab3FEPrU (ORCPT ); Wed, 5 Jun 2013 11:47:20 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,807,1363158000"; d="scan'208";a="348644793" Message-ID: <51AF5D82.1090308@linux.intel.com> Date: Wed, 05 Jun 2013 18:47:14 +0300 From: Eliezer Tamir User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Eric Dumazet CC: David Miller , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jesse Brandeburg , Don Skidmore , e1000-devel@lists.sourceforge.net, Willem de Bruijn , Ben Hutchings , Andi Kleen , HPA , Eilon Greenstien , Or Gerlitz , Amir Vadai , Eliezer Tamir Subject: Re: [PATCH v9 net-next 5/7] net: simple poll/select low latency socket poll References: <20130605103400.11172.49099.stgit@ladj378.jer.intel.com> <20130605103452.11172.31453.stgit@ladj378.jer.intel.com> <1370439054.24311.248.camel@edumazet-glaptop> <51AF401C.2030506@linux.intel.com> <1370445606.24311.265.camel@edumazet-glaptop> In-Reply-To: <1370445606.24311.265.camel@edumazet-glaptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 32 On 05/06/2013 18:20, Eric Dumazet wrote: > On Wed, 2013-06-05 at 16:41 +0300, Eliezer Tamir wrote: >> On 05/06/2013 16:30, Eric Dumazet wrote: > >>> I am a bit uneasy with this one, because an applicatio polling() on one >>> thousand file descriptors using select()/poll(), will call sk_poll_ll() >>> one thousand times. >> >> But we call sk_poll_ll() with nonblock set, so it will only test once >> for each socket and not loop. >> >> I think this is not as bad as it sounds. >> We still honor the time limit on how long to poll. > > We still call ndo_ll_poll() a thousand times, and probably do a > spinlock/unlock a thousand times in the driver. > > I would definitely be convinced if you give us some performance numbers > of a poll() on a thousand tcp sockets for example. So with 1000 sockets this is defiantly not a win sockperf with 1000 udp sockets sysctl 50 0 select 178.5 us / 130.0 us poll 188.6 us / 130.0 us -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/