From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw1-f70.google.com (mail-yw1-f70.google.com [209.85.161.70]) by kanga.kvack.org (Postfix) with ESMTP id C1DA96B4D47 for ; Wed, 28 Nov 2018 08:59:05 -0500 (EST) Received: by mail-yw1-f70.google.com with SMTP id r194so1030165ywg.12 for ; Wed, 28 Nov 2018 05:59:05 -0800 (PST) Received: from p3plsmtpa06-07.prod.phx3.secureserver.net (p3plsmtpa06-07.prod.phx3.secureserver.net. [173.201.192.108]) by mx.google.com with ESMTPS id p15-v6si4873445ybg.427.2018.11.28.05.59.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 Nov 2018 05:59:04 -0800 (PST) Subject: Re: [PATCH v2 0/6] RFC: gup+dma: tracking dma-pinned pages References: <20181110085041.10071-1-jhubbard@nvidia.com> <942cb823-9b18-69e7-84aa-557a68f9d7e9@talpey.com> <97934904-2754-77e0-5fcb-83f2311362ee@nvidia.com> <5159e02f-17f8-df8b-600c-1b09356e46a9@talpey.com> <15e4a0c0-cadd-e549-962f-8d9aa9fc033a@talpey.com> <313bf82d-cdeb-8c75-3772-7a124ecdfbd5@nvidia.com> From: Tom Talpey Message-ID: <2aa422df-d5df-5ddb-a2e4-c5e5283653b5@talpey.com> Date: Wed, 28 Nov 2018 08:59:01 -0500 MIME-Version: 1.0 In-Reply-To: <313bf82d-cdeb-8c75-3772-7a124ecdfbd5@nvidia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: John Hubbard , john.hubbard@gmail.com, linux-mm@kvack.org Cc: Andrew Morton , LKML , linux-rdma , linux-fsdevel@vger.kernel.org On 11/27/2018 9:52 PM, John Hubbard wrote: > On 11/27/18 5:21 PM, Tom Talpey wrote: >> On 11/21/2018 5:06 PM, John Hubbard wrote: >>> On 11/21/18 8:49 AM, Tom Talpey wrote: >>>> On 11/21/2018 1:09 AM, John Hubbard wrote: >>>>> On 11/19/18 10:57 AM, Tom Talpey wrote: > [...] >>>> >>>> What I'd really like to see is to go back to the original fio parameters >>>> (1 thread, 64 iodepth) and try to get a result that gets at least close >>>> to the speced 200K IOPS of the NVMe device. There seems to be something >>>> wrong with yours, currently. >>> >>> I'll dig into what has gone wrong with the test. I see fio putting data files >>> in the right place, so the obvious "using the wrong drive" is (probably) >>> not it. Even though it really feels like that sort of thing. We'll see. >>> >>>> >>>> Then of course, the result with the patched get_user_pages, and >>>> compare whichever of IOPS or CPU% changes, and how much. >>>> >>>> If these are within a few percent, I agree it's good to go. If it's >>>> roughly 25% like the result just above, that's a rocky road. >>>> >>>> I can try this after the holiday on some basic hardware and might >>>> be able to scrounge up better. Can you post that github link? >>>> >>> >>> Here: >>> >>>     git@github.com:johnhubbard/linux (branch: gup_dma_testing) >> >> I'm super-limited here this week hardware-wise and have not been able >> to try testing with the patched kernel. >> >> I was able to compare my earlier quick test with a Bionic 4.15 kernel >> (400K IOPS) against a similar 4.20rc3 kernel, and the rate dropped to >> ~_375K_ IOPS. Which I found perhaps troubling. But it was only a quick >> test, and without your change. >> > > So just to double check (again): you are running fio with these parameters, > right? > > [reader] > direct=1 > ioengine=libaio > blocksize=4096 > size=1g > numjobs=1 > rw=read > iodepth=64 Correct, I copy/pasted these directly. I also ran with size=10g because the 1g provides a really small sample set. There was one other difference, your results indicated fio 3.3 was used. My Bionic install has fio 3.1. I don't find that relevant because our goal is to compare before/after, which I haven't done yet. Tom. > > > >> Say, that branch reports it has not had a commit since June 30. Is that >> the right one? What about gup_dma_for_lpc_2018? >> > > That's the right branch, but the AuthorDate for the head commit (only) somehow > got stuck in the past. I just now amended that patch with a new date and pushed > it, so the head commit now shows Nov 27: > > https://github.com/johnhubbard/linux/commits/gup_dma_testing > > > The actual code is the same, though. (It is still based on Nov 19th's f2ce1065e767 > commit.) > > > thanks, >