From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH 02/16] user_ns: use new hashtable implementation Date: Wed, 15 Aug 2012 03:35:17 +0200 Message-ID: <502AFCD5.6070104@gmail.com> References: <1344961490-4068-1-git-send-email-levinsasha928@gmail.com> <1344961490-4068-3-git-send-email-levinsasha928@gmail.com> <87txw5hw0s.fsf@xmission.com> <502AF184.4010907@gmail.com> <87393phshy.fsf@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: torvalds@linux-foundation.org, tj@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu, aarcange@redhat.com, ericvh@gmail.com, netdev@vger.kernel.org, josh@joshtriplett.org, eric.dumazet@gmail.com, mathieu.desnoyers@efficios.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com, teigland@redhat.com, Trond.Myklebust@netapp.com, bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com, venkat.x.venkatsubra@oracle.com, ejt@redhat.com, snitzer@redhat.com, edumazet@google.com, linux-nfs@vger.kernel.org, dev@openvswitch.org, rds-devel@oss.oracle.com, lw@cn.fujitsu.com To: "Eric W. Biederman" Return-path: In-Reply-To: <87393phshy.fsf@xmission.com> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org On 08/15/2012 03:08 AM, Eric W. Biederman wrote: >> I can offer the following: I'll write a small module that will hash 1...10000 >> > into a hashtable which uses 7 bits (just like user_ns) and post the distribution >> > we'll get. > That won't hurt. I think 1-100 then 1000-1100 may actually be more > representative. Not that I would mind seeing the larger range. > Especially since I am in the process of encouraging the use of more > uids. > Alrighty, the results are in (numbers are objects in bucket): For the 0...10000 range: Average: 78.125 Std dev: 1.4197704151 Min: 75 Max: 80 For the 1...100 range: Average: 0.78125 Std dev: 0.5164613088 Min: 0 Max: 2 For the 1000...1100 range: Average: 0.7890625 Std dev: 0.4964812206 Min: 0 Max: 2 Looks like hash_32 is pretty good with small numbers. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org