RPI3 swap experiments (r338342 with vm.pageout_oom_seq="1024")

[Mark Millard]

On 2018-Sep-1, at 4:02 PM, bob prohaska <fbsd at www.zefox.net> wrote:

> On Wed, Aug 15, 2018 at 03:55:04PM -0700, bob prohaska wrote:
>> 
>> When I started this goose chase, after zero problems with RPI2, I thought the
>> issue was arm64-related and might be of some fundamental importance.
>> 
>> Thanks to many people I now understand it's a confluence of USB and flash memory
>> artifacts, made evident by the demands of clang6. Elsewhere I noted that I'm seeking
>> "the robustness of a Mars rover, using a rack server OS on a cellphone motherboard".
>> 
> 
> With r338342  and
> vm.pageout_oom_seq="1024"
> in /boot/loader.conf the RPI3 is a bit closer to a Mars Rover.
> No panics, crashes or USB errors, -j4 buildworld runs to completion.
> When swap usage goes over about 50% the system slows, but doesn't give up.
> There are six 1 GB swap partitions available, 3 on USB and 3 on microSD.
> 
> Log files are at
> http://www.zefox.net/~fbsd/rpi3/swaptests/r338342/
> for the combinations tried so far.

http://www.zefox.net/~fbsd/rpi3/swaptests/r338342/2gbsd/swapscript.log

shows things like:

dT: 10.043s  w: 10.000s
 L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w    d/s   kBps   ms/d   %busy Name
    0    126     19    122    2.3    107   2034    3.3      0      0    0.0   29.2  da0
    0     67      0      0    0.0     67   1126    2.5      0      0    0.0   16.6  da0f
    0     59     19    122    2.3     40    909    4.7      0      0    0.0   14.7  da0g

as well as:

dT: 10.004s  w: 10.000s
 L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w    d/s   kBps   ms/d   %busy Name
    4    412     32    324   11.2    380   2945    7.9      0      0    0.0   80.2  mmcsd0
    0      1      1     26    4.7      0      0    0.0      0      0    0.0    0.4  da0
    4    412     32    324   11.5    380   2945    8.0      0      0    0.0   80.8  mmcsd0s2
    2    205     15    160   10.6    190   1453    8.0      0      0    0.0   78.7  mmcsd0s2d
    2    207     17    165   12.3    190   1491    8.0      0      0    0.0   78.6  mmcsd0s2e
    0      0      0      0    0.0      0      1   17.5      0      0    0.0    0.2  mmcsd0s2a
    0      0      0      0    0.0      0      1   17.6      0      0    0.0    0.2  ufs/rootfs
    0      1      1     26    4.8      0      0    0.0      0      0    0.0    0.4  da0g

It is not clear what partitions were in use for what types of
data. da0f, da0g, mmcsd0s2d, and mmcsd0s2e: are they all
swap partitions? If yes, then the the test log does not appear
to be a "2gbsd" test.



Ignoring such points: Are these tests using the same devices that logged
errors to the console in all that prior testing?

If yes: Having such errors stop is potentially interesting.


===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)