RPI3 swap experiments

Fri Jun 29 23:00:20 UTC 2018

Mark Millard wrote on 30/06/2018 00:35:
> 
> 
> On 2018-Jun-29, at 5:28 AM, Trev <freebsd-arm at sentry.org> wrote:
> 
> 
>> Jun 29 20:20:35 rpi3 kernel: pid 66844 (c++), uid 0, was killed: out of swap space
>>
>> At the time of "out of swap" only 157M of the 4G swap was in use. The 4GB swap partition is on a 4GB USB2 memory key (da1p1), everything else is on the sdcard. There are no excessively long ms/w being recorded. There are no USB or other related errors.
> 
> Good to know.
> 
>> top and gstat stats leading up to the process being killed are below.
>>
>> last pid: 66931;  load averages:  3.23,  3.14,  3.25  up 0+03:18:04 20:20:16
>> 47 processes:  3 running, 44 sleeping
>>
>> Mem: 647M Active, 25M Inact, 22M Laundry, 188M Wired, 97M Buf, 19M Free
>> Swap: 4044M Total, 136M Used, 3908M Free, 3% Inuse
>>     1     15      0      0    0.0     15    607   65.0   97.4  mmcsd0s2a
>>     4     17      7     56    2.0     10    120    8.9    4.2  da1p1
>>
>> last pid: 66936;  load averages:  3.29,  3.16,  3.25  up 0+03:18:08 20:20:20
>> 47 processes:  4 running, 43 sleeping
>>
>> Mem: 664M Active, 5732K Inact, 27M Laundry, 184M Wired, 97M Buf, 19M Free
>> Swap: 4044M Total, 138M Used, 3906M Free, 3% Inuse
>>     1     13      0      0    0.0     13    527   58.8   74.7  mmcsd0s2a
>>     4     34      2     20    2.9     32   2187   40.4   40.8  da1p1
>>
>> last pid: 66941;  load averages:  3.35,  3.17,  3.25  up 0+03:18:13 20:20:25
>> 47 processes:  3 running, 44 sleeping
>>
>> Mem: 644M Active, 524K Inact, 58M Laundry, 183M Wired, 97M Buf, 15M Free
>> Swap: 4044M Total, 140M Used, 3904M Free, 3% Inuse
>>     0      3      0      0    0.0      3     96   98.0   29.1  mmcsd0s2a
>>     5     42      0      0    0.0     42   2205   88.9   99.8  da1p1
>>
>> last pid: 66946;  load averages:  3.32,  3.17,  3.25  up 0+03:18:17 20:20:29
>> 47 processes:  3 running, 44 sleeping
>>
>> Mem: 601M Active, 420K Inact, 96M Laundry, 184M Wired, 97M Buf, 20M Free
>> Swap: 4044M Total, 150M Used, 3893M Free, 3% Inuse
>>     1      1      0      0    0.0      1     96  169.5   16.9  mmcsd0s2a
>>     0    102      5     32  158.3     97   1357   38.2   93.8  da1p1
>>
>> last pid: 66951;  load averages:  3.38,  3.18,  3.26  up 0+03:18:21 20:20:33
>> 47 processes:  3 running, 44 sleeping
>>
>> Mem: 271M Active, 339M Inact, 89M Laundry, 184M Wired, 97M Buf, 18M Free
>> Swap: 4044M Total, 157M Used, 3887M Free, 3% Inuse
>>     0      7      0      0    0.0      7    223   79.4   55.4  mmcsd0s2a
>>     5      0      0      0    0.0      0      0    0.0    0.0  da1p1
>>
>> [OUT OF SWAP OCCURS HERE at 20:20:35 - 2 secs after the above and 2 secs before the below]
>>
>> last pid: 66957;  load averages:  3.34,  3.18,  3.25  up 0+03:18:25 20:20:37
>> 47 processes:  3 running, 44 sleeping
>>
>> Mem: 233M Active, 680K Inact, 296M Laundry, 184M Wired, 98M Buf, 187M Free
>> Swap: 4044M Total, 157M Used, 3887M Free, 3% Inuse
>>     0      0      0      0    0.0      0      0    0.0    0.0  mmcsd0s2a
>>     6      0      0      0    0.0      0      0    0.0    0.0  da1p1
> 
> Just for reference/context:
> 
> uname -apKU
> 
> output?

  % uname -apKU
FreeBSD rpi3.sentry.org 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r335317: 
Mon Jun 18 17:37:04 UTC 2018 
root at releng3.nyi.freebsd.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC 
arm64 aarch64 1200069 1200069

FreeBSD-12.0-CURRENT-arm64-aarch64-RPI3-20180618-r335317.img at:
https://download.freebsd.org/ftp/snapshots/arm64/aarch64/ISO-IMAGES/12.0/FreeBSD-12.0-CURRENT-arm64-aarch64-RPI3-20180618-r335317.img.xz

> How would someone repeat your steps to set up
> and start a similar test?

% cat /etc/fstab
# Custom /etc/fstab for FreeBSD embedded images
/dev/ufs/rootfs   /       ufs     rw,noatime      1       1
/dev/msdosfs/MSDOSBOOT /boot/msdos msdosfs rw,noatime 0 0
md1 /tmp mfs rw,noatime,-s100m 0 0
md2 /var/log mfs rw,noatime,-s15m 0 0
md3 /var/tmp mfs rw,noatime,-s15m 0 0
/dev/da1p1    none    swap    sw      0       0
#/dev/ufs/usr   /usr    ufs     rw,noatime      2       2

16GB SanDisk Ultra micro sdcard (12 current snapshot from 18 June):

% gpart show -l mmcsd
=>      63  31116225  mmcsd0  MBR  (15G)
         63      2016          - free -  (1.0M)
       2079    102312       1  (null)  [active]  (50M)
     104391  31008825       2  (null)  (15G)
   31113216      3072          - free -  (1.5M)

% gpart show -l mmcsd0s2
=>       0  31008825  mmcsd0s2  BSD  (15G)
          0        57            - free -  (29K)
         57  31008768         1  (null)  (15G)

% gpart show -l da1
=>     40  8282032  da1  GPT  (3.9G)
        40  8282032    1  usbswap  (3.9G)

Promotional 4GB USB2 memory key from UNSW Law Faculty :)

da1: <General UDisk 5.00> Removable Direct Access SCSI-2 device
da1: 40.000MB/s transfers
da1: 4044MB (8282112 512 byte sectors)
da1: quirks=0x2<NO_6_BYTE>