Return-Path: linux-nfs-owner@vger.kernel.org Received: from smtp.opengridcomputing.com ([72.48.136.20]:34482 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752822Ab3D2NFk (ORCPT ); Mon, 29 Apr 2013 09:05:40 -0400 Message-ID: <517E701F.1010807@opengridcomputing.com> Date: Mon, 29 Apr 2013 08:05:35 -0500 From: Tom Tucker MIME-Version: 1.0 To: Yan Burman CC: Wendy Cheng , "J. Bruce Fields" , "Atchley, Scott" , "linux-rdma@vger.kernel.org" , "linux-nfs@vger.kernel.org" , Or Gerlitz Subject: Re: NFS over RDMA benchmark References: <0EE9A1CDC8D6434DB00095CD7DB873462CF96C65@MTLDAG01.mtl.com> <62745258-4F3B-4C05-BFFD-03EA604576E4@ornl.gov> <0EE9A1CDC8D6434DB00095CD7DB873462CF9715B@MTLDAG01.mtl.com> <20130423210607.GJ3676@fieldses.org> <0EE9A1CDC8D6434DB00095CD7DB873462CF988C9@MTLDAG01.mtl.com> <20130424150540.GB20275@fieldses.org> <20130424152631.GC20275@fieldses.org> <0EE9A1CDC8D6434DB00095CD7DB873462CF9A820@MTLDAG01.mtl.com> <20130428144248.GA2037@fieldses.org> <0EE9A1CDC8D6434DB00095CD7DB873462CF9B3E7@MTLDAG01.mtl.com> In-Reply-To: <0EE9A1CDC8D6434DB00095CD7DB873462CF9B3E7@MTLDAG01.mtl.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 4/29/13 7:16 AM, Yan Burman wrote: > >> -----Original Message----- >> From: Wendy Cheng [mailto:s.wendy.cheng@gmail.com] >> Sent: Monday, April 29, 2013 08:35 >> To: J. Bruce Fields >> Cc: Yan Burman; Atchley, Scott; Tom Tucker; linux-rdma@vger.kernel.org; >> linux-nfs@vger.kernel.org; Or Gerlitz >> Subject: Re: NFS over RDMA benchmark >> >> On Sun, Apr 28, 2013 at 7:42 AM, J. Bruce Fields wrote: >> >>>> On Wed, Apr 17, 2013 at 7:36 AM, Yan Burman >>>> When running ib_send_bw, I get 4.3-4.5 GB/sec for block sizes 4-512K. >>>> When I run fio over rdma mounted nfs, I get 260-2200MB/sec for the >>>> same block sizes (4-512K). running over IPoIB-CM, I get 200-980MB/sec. >>> ... >> [snip] >> >>>> 36.18% nfsd [kernel.kallsyms] [k] mutex_spin_on_owner >>> That's the inode i_mutex. >>> >>>> 14.70%-- svc_send >>> That's the xpt_mutex (ensuring rpc replies aren't interleaved). >>> >>>> 9.63% nfsd [kernel.kallsyms] [k] _raw_spin_lock_irqsave >>>> >>> And that (and __free_iova below) looks like iova_rbtree_lock. >>> >>> >> Let's revisit your command: >> >> "FIO arguments: --rw=randread --bs=4k --numjobs=2 --iodepth=128 -- >> ioengine=libaio --size=100000k --prioclass=1 --prio=0 --cpumask=255 >> --loops=25 --direct=1 --invalidate=1 --fsync_on_close=1 --randrepeat=1 -- >> norandommap --group_reporting --exitall --buffered=0" >> > I tried block sizes from 4-512K. > 4K does not give 2.2GB bandwidth - optimal bandwidth is achieved around 128-256K block size > >> * inode's i_mutex: >> If increasing process/file count didn't help, maybe increase "iodepth" >> (say 512 ?) could offset the i_mutex overhead a little bit ? >> > I tried with different iodepth parameters, but found no improvement above iodepth 128. > >> * xpt_mutex: >> (no idea) >> >> * iova_rbtree_lock >> DMA mapping fragmentation ? I have not studied whether NFS-RDMA >> routines such as "svc_rdma_sendto()" could do better but maybe sequential >> IO (instead of "randread") could help ? Bigger block size (instead of 4K) can >> help ? >> I think the biggest issue is that max_payload for TCP is 2MB but only 256k for RDMA. > I am trying to simulate real load (more or less), that is the reason I use randread. Anyhow, read does not result in better performance. > It's probably because backing storage is tmpfs... > > Yan > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html