Comment 4 for bug 1698118

This bug affects me too.

$ uname -a
Linux aammscott 4.8.0-54-generic #57~16.04.1-Ubuntu SMP Wed May 24 16:20:44 UTC 2017 i686 i686 i686 GNU/Linux

-Version-
Kernel : Linux 4.8.0-54-generic (i686)
Distribution : Ubuntu 16.04.2 LTS

-Board-
Name : P8H77-V LE
Vendor : ASUSTeK COMPUTER INC. (SEAGATE, www.seagate.com)

-Computer-
Processor : 4x Intel(R) Core(TM) i5-3450 CPU @ 3.10GHz
Memory : 16552MB (1441MB used)

-SCSI Disks-
ATA Crucial_CT2050MX
Optiarc DVD RW AD-7280S

Originally reported

https://ubuntuforums.org/showthread.php?t=2363087&highlight=

I used the same tests as above, with the following modifications:
- Not run as root (NEVER RUN rm -rf AS ROOT!)
- cwd set to ~/tmp (mkdir /tmp if you need to)

My results on my 16 GB RAM 32 bit install of 16.04.02 (updated) are:

Copying /lib to 1: 8.95
Copying 1 to 2: 18.01
Copying 2 to 3: 10.79
Copying 3 to 4: 10.23
Copying 4 to 5: 8.94
Copying 5 to 6: 8.70
Copying 6 to 7: 8.50
Copying 7 to 8: 8.00
Copying 8 to 9: 9.25
Copying 9 to 0: 9.55
Copying 0 to 1: 9.69
Copying 1 to 2: 12.30
Copying 2 to 3: 16.05
Copying 3 to 4: 36.38
Copying 4 to 5: 212.44
Copying 5 to 6: 323.97

To me that is a clear reproduction.

I then booted into the live cd of 64 bit 16.04.02, and mounted all my file systems, just as though I was going to reinstall grub, and also mounted my separate /home partition, all under /mnt. I chrooted into /mnt, ran sudo -su <username> to limit myself to normal user privileges, then ran the same test. Results are:

Copying /lib to 1: 8.07
Copying 1 to 2: 1.00
Copying 2 to 3: 1.63
Copying 3 to 4: 1.63
Copying 4 to 5: 1.89
Copying 5 to 6: 2.77
Copying 6 to 7: 2.08
Copying 7 to 8: 1.81
Copying 8 to 9: 1.79
Copying 9 to 0: 1.95
Copying 0 to 1: 1.68
Copying 1 to 2: 1.45
Copying 2 to 3: 1.55
Copying 3 to 4: 1.75
Copying 4 to 5: 1.38
Copying 5 to 6: 1.55
Copying 6 to 7: 1.60
Copying 7 to 8: 1.78
Copying 8 to 9: 1.24
Copying 9 to 0: 1.44
Copying 0 to 1: 1.58
Copying 1 to 2: 1.76
Copying 2 to 3: 1.49
Copying 3 to 4: 1.47
Copying 4 to 5: 1.50
Copying 5 to 6: 1.55
Copying 6 to 7: 1.25
Copying 7 to 8: 1.51
Copying 8 to 9: 1.54
Copying 9 to 0: 1.84
Copying 0 to 1: 2.20
Copying 1 to 2: 2.54
Copying 2 to 3: 2.74
Copying 3 to 4: 2.78
Copying 4 to 5: 2.78
Copying 5 to 6: 2.52
Copying 6 to 7: 2.47
Copying 7 to 8: 2.77
Copying 8 to 9: 1.90
Copying 9 to 0: 2.68
Copying 0 to 1: 2.44
Copying 1 to 2: 2.66
Copying 2 to 3: 2.38
Copying 3 to 4: 2.70
Copying 4 to 5: 2.68
Copying 5 to 6: 2.67
Copying 6 to 7: 2.21
Copying 7 to 8: 2.55
Copying 8 to 9: 2.73
Copying 9 to 0: 2.70
Copying 0 to 1: 2.17
Copying 1 to 2: 2.49
Copying 2 to 3: 2.66
Copying 3 to 4: 2.83
Copying 4 to 5: 2.43
Copying 5 to 6: 2.63
Copying 6 to 7: 2.47
Copying 7 to 8: 2.81
Copying 8 to 9: 2.58

Conclusions:

- Bug only affects 32 bit installs with 16 GB RAM (or more?)
- IO performance under 64 bit on my hardware is 4-5 times better in any case.