From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933027AbbIUXzi (ORCPT ); Mon, 21 Sep 2015 19:55:38 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:30828 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756163AbbIUXzg (ORCPT ); Mon, 21 Sep 2015 19:55:36 -0400 Subject: Re: [PATCH 05/15] RDS: increase size of hash-table to 8K To: David Miller References: <1442703892-26692-1-git-send-email-santosh.shilimkar@oracle.com> <1442703892-26692-6-git-send-email-santosh.shilimkar@oracle.com> <20150921.160527.1218605543469993281.davem@davemloft.net> Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ssantosh@kernel.org From: santosh shilimkar Organization: Oracle Corporation Message-ID: <560098ED.7@oracle.com> Date: Mon, 21 Sep 2015 16:55:25 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150921.160527.1218605543469993281.davem@davemloft.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/21/2015 4:05 PM, David Miller wrote: > From: Santosh Shilimkar > Date: Sat, 19 Sep 2015 19:04:42 -0400 > >> Even with per bucket locking scheme, in a massive parallel >> system with active rds sockets which could be in excess of multiple >> of 10K, rds_bin_lookup() workload is siginificant because of smaller >> hashtable size. >> >> With some tests, it was found that we get modest but still nice >> reduction in rds_bind_lookup with bigger bucket. >> >> Hashtable Baseline(1k) Delta >> 2048: 8.28% -2.45% >> 4096: 8.28% -4.60% >> 8192: 8.28% -6.46% >> 16384: 8.28% -6.75% >> >> Based on the data, we set 8K as the bind hash-table size. >> >> Signed-off-by: Santosh Shilimkar >> Signed-off-by: Santosh Shilimkar > > Like others I would strongly prefer that you use a dynamically sized > hash table. > > Eating 8k just because a module just happened to get loaded is really > not appropriate. > > And there are many other places that use such a scheme, one example is > the AF_NETLINK socket hash table. OK. Thanks for AF_NETLINK pointer. I will look it up. Regards, Santosh