From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Talpey Subject: Re: [PATCH v2 0/6] RFC: gup+dma: tracking dma-pinned pages Date: Thu, 29 Nov 2018 21:30:13 -0500 Message-ID: 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> <2aa422df-d5df-5ddb-a2e4-c5e5283653b5@talpey.com> <7a68b7fc-ff9d-381e-2444-909c9c2f6679@nvidia.com> <1939f47a-eaec-3f2c-4ae7-f92d9fba7693@talpey.com> <0f093af1-dee9-51b6-0795-2c073a951fed@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <0f093af1-dee9-51b6-0795-2c073a951fed@nvidia.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: John Hubbard , john.hubbard@gmail.com, linux-mm@kvack.org Cc: Andrew Morton , LKML , linux-rdma , linux-fsdevel@vger.kernel.org List-Id: linux-rdma@vger.kernel.org On 11/29/2018 9:21 PM, John Hubbard wrote: > On 11/29/18 6:18 PM, Tom Talpey wrote: >> On 11/29/2018 8:39 PM, John Hubbard wrote: >>> On 11/28/18 5:59 AM, Tom Talpey wrote: >>>> 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: >>>>> [...] >>>>>> 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. >>>> >>> >>> OK, the 50 MB/s was due to my particular .config. I had some expensive debug options >>> set in mm, fs and locking subsystems. Turning those off, I'm back up to the rated >>> speed of the Samsung NVMe device, so now we should have a clearer picture of the >>> performance that real users will see. >> >> Oh, good! I'm especially glad because I was having a heck of a time >> reconfiguring the one machine I have available for this. >> >>> Continuing on, then: running a before and after test, I don't see any significant >>> difference in the fio results: >> >> Excerpting from below: >> >>> Baseline 4.20.0-rc3 (commit f2ce1065e767), as before: >>>      read: IOPS=193k, BW=753MiB/s (790MB/s)(1024MiB/1360msec) >>>     cpu          : usr=16.26%, sys=48.05%, ctx=251258, majf=0, minf=73 >> >> vs >> >>> With patches applied: >>>      read: IOPS=193k, BW=753MiB/s (790MB/s)(1024MiB/1360msec) >>>     cpu          : usr=16.26%, sys=48.05%, ctx=251258, majf=0, minf=73 >> >> Perfect results, not CPU limited, and full IOPS. >> >> Curiously identical, so I trust you've checked that you measured >> both targets, but if so, I say it's good. >> > > Argh, copy-paste error in the email. The real "before" is ever so slightly > better, at 194K IOPS and 759 MB/s: Definitely better - note the system CPU is lower, which is probably the reason for the increased IOPS. > cpu : usr=18.24%, sys=44.77%, ctx=251527, majf=0, minf=73 Good result - a correct implementation, and faster. Tom. > > $ fio ./experimental-fio.conf > reader: (g=0): rw=read, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64 > fio-3.3 > Starting 1 process > Jobs: 1 (f=1) > reader: (groupid=0, jobs=1): err= 0: pid=1715: Thu Nov 29 17:07:09 2018 > read: IOPS=194k, BW=759MiB/s (795MB/s)(1024MiB/1350msec) > slat (nsec): min=1245, max=2812.7k, avg=1538.03, stdev=5519.61 > clat (usec): min=148, max=755, avg=326.85, stdev=18.13 > lat (usec): min=150, max=3483, avg=328.41, stdev=19.53 > clat percentiles (usec): > | 1.00th=[ 322], 5.00th=[ 326], 10.00th=[ 326], 20.00th=[ 326], > | 30.00th=[ 326], 40.00th=[ 326], 50.00th=[ 326], 60.00th=[ 326], > | 70.00th=[ 326], 80.00th=[ 326], 90.00th=[ 326], 95.00th=[ 326], > | 99.00th=[ 355], 99.50th=[ 537], 99.90th=[ 553], 99.95th=[ 553], > | 99.99th=[ 619] > bw ( KiB/s): min=767816, max=783096, per=99.84%, avg=775456.00, stdev=10804.59, samples=2 > iops : min=191954, max=195774, avg=193864.00, stdev=2701.15, samples=2 > lat (usec) : 250=0.09%, 500=99.30%, 750=0.61%, 1000=0.01% > cpu : usr=18.24%, sys=44.77%, ctx=251527, majf=0, minf=73 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0% > issued rwts: total=262144,0,0,0 short=0,0,0,0 dropped=0,0,0,0 > latency : target=0, window=0, percentile=100.00%, depth=64 > > Run status group 0 (all jobs): > READ: bw=759MiB/s (795MB/s), 759MiB/s-759MiB/s (795MB/s-795MB/s), io=1024MiB (1074MB), run=1350-1350msec > > Disk stats (read/write): > nvme0n1: ios=222853/0, merge=0/0, ticks=71410/0, in_queue=71935, util=100.00% > > thanks, >