/proc/diskstats does not rollup queue depth from partitions

[Albert Autin]

Tested in Ubuntu 18.04LTS and Ubuntu 18.10, with the same result. The queue size rollup works in Centos 7 though.

root@vagrant:~# uname -a
Linux vagrant 4.18.0-12-generic #13-Ubuntu SMP Wed Nov 14 15:17:05 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

root@vagrant:~# lsb_release -rd
Description: Ubuntu 18.10
Release: 18.10

root@vagrant:~# cat /proc/diskstats
   7 0 loop0 5 0 16 0 0 0 0 0 0 0 0
   7 1 loop1 0 0 0 0 0 0 0 0 0 0 0
   7 2 loop2 0 0 0 0 0 0 0 0 0 0 0
   7 3 loop3 0 0 0 0 0 0 0 0 0 0 0
   7 4 loop4 0 0 0 0 0 0 0 0 0 0 0
   7 5 loop5 0 0 0 0 0 0 0 0 0 0 0
   7 6 loop6 0 0 0 0 0 0 0 0 0 0 0
   7 7 loop7 0 0 0 0 0 0 0 0 0 0 0
 259 0 nvme0n1 813340 0 10963704 274028 4075 44 1040576 46884 0 18012 908472
 259 5 nvme0n1p1 203838 0 2749463 65696 986 0 252416 11696 13 14360 218028
 259 6 nvme0n1p2 202672 0 2713358 67924 1015 0 259840 11696 20 14372 220388
 259 7 nvme0n1p3 202961 0 2717301 70464 1034 0 264704 11652 19 14344 226248
 259 8 nvme0n1p4 203216 0 2730974 69944 1028 0 263168 11840 16 14340 224992
   8 0 sda 11622 783 612090 16416 6529 9730 607624 52912 0 7964 76940
   8 1 sda1 11543 783 607954 16408 4731 9730 607624 52844 0 7380 76304
 253 0 dm-0 12083 0 598666 25540 16198 0 613808 137252 0 7936 162808
 253 1 dm-1 186 0 8696 104 0 0 0 0 0 80 104

We expect the queue depth of 'nvme0n1' to increase when the partitions it has increase, but this never happens.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1807432

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Albert Autin (alb0t)]

Here is the details on a bare metal ubuntu 18.04 LTS server running an IO benchmark:
# uname -a
Linux xxx 4.15.0-39-generic #42-Ubuntu SMP Tue Oct 23 15:48:01 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

# lsb_release -rd
Description: Ubuntu 18.04.1 LTS
Release: 18.04

# cat /proc/diskstats
   7 0 loop0 0 0 0 0 0 0 0 0 0 0 0
   7 1 loop1 0 0 0 0 0 0 0 0 0 0 0
   7 2 loop2 0 0 0 0 0 0 0 0 0 0 0
   7 3 loop3 0 0 0 0 0 0 0 0 0 0 0
   7 4 loop4 0 0 0 0 0 0 0 0 0 0 0
   7 5 loop5 0 0 0 0 0 0 0 0 0 0 0
   7 6 loop6 0 0 0 0 0 0 0 0 0 0 0
   7 7 loop7 0 0 0 0 0 0 0 0 0 0 0
   8 0 sda 42531 5065 2097514 177892 7213856 2831260 295763362 4616524 0 1535632 4790132
   8 1 sda1 221 30 11808 632 2 0 2 0 0 436 632
   8 2 sda2 42146 5033 2077442 176336 7213854 2831260 295763360 4616524 0 1535412 4788584
   8 16 sdb 77529 0 39360314 52284 613197 114047 198167776 23144 0 29212 74964
   8 17 sdb1 77078 0 39335602 52052 613197 114047 198167776 23144 0 29100 74732
 259 0 nvme0n1 28201525398 0 488820005576 207589544 862135419 98 226957567536 127289372 0 389795644 709789780
 259 11 nvme0n1p1 2417230384 0 71713692888 554246764 155623487 0 39839572992 14866796 7 116086276 414538992
 259 12 nvme0n1p2 2417484200 0 71743882112 553922380 155595754 0 39832473344 14030424 8 115793704 412547176
 259 13 nvme0n1p3 2415958954 0 71634470992 554243464 155462257 0 39798298112 14474168 10 115988052 413090312
 259 14 nvme0n1p4 2416615620 0 71693490456 554028440 155535038 0 39816930048 13413172 5 115578348 412099184
 259 5 nvme1n1 9665715778 0 286976448416 2212243248 622132262 98 165516759344 56229716 0 296178992 2019232932
 259 20 nvme1n1p1 2415904567 0 71636878008 552917888 155454273 0 39796254208 14455924 5 116082548 412220948
 259 21 nvme1n1p2 2415512074 0 71650757824 552297300 155569570 0 39825770240 13910420 5 115679536 412130316
 259 22 nvme1n1p3 2416548713 0 71678672568 553555664 155500210 0 39808014080 14275504 3 116157680 412450228
 259 23 nvme1n1p4 2416416216 0 71684681400 553144864 155607183 0 39835399168 13506844 9 115654900 412532936
 253 0 dm-0 46520 0 2049706 243712 9679815 0 295763360 4748384 0 1543256 4994124
 259 10 nvme2n1 9667389541 0 287031008544 2207928032 622164931 98 165525122608 56921664 0 295218964 2002099520
 259 6 nvme2n1p1 2417118800 0 71696213648 552051652 155532183 0 39816199168 14594732 12 115840944 412346808
 259 7 nvme2n1p2 2416691746 0 71684078312 551562408 155534110 0 39816692480 14208680 7 115539968 410287704
 259 8 nvme2n1p3 2416582480 0 71718109272 552480036 155634065 0 39842280960 14504168 5 115924508 411293804
 259 9 nvme2n1p4 2415651523 0 71604404864 551508236 155463547 0 39798628352 13532972 7 115275812 409783788
 259 15 nvme3n1 9667640590 0 287047711752 2205542280 622265688 98 165550916400 56371312 0 295252232 2008945404
 259 1 nvme3n1p1 2417190392 0 71723552872 551558532 155625698 0 39840139008 14546232 1 115786248 410727612
 259 2 nvme3n1p2 2415650590 0 71604369040 550597652 155449331 0 39794989056 13932652 1 115166100 409314844
 259 3 nvme3n1p3 24...

[Albert Autin (alb0t)]

These are all the logs I have...

[Kai-Heng Feng (kaihengfeng)]

Please test latest mainline kernel:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.3-rc2/