CURRENT slow and shaky network stability

[Don Lewis]

On 26 Mar, Poul-Henning Kamp wrote:
> --------
> In message <CANJ8om5rkNAuY0j-undf9A8stJ1LD2yHo4xfqgG1qODeAGvqVA at mail.gmail.com>
> , Ultima writes:
> 
>> A large zfs send [...]
> 
> I am not running zfs.

I am.  I'm not seeing any unexpected problems.  I haven't really loaded
this system up with a big poudriere run since it's been booted.  It's
mostly just been singled-threaded compiles since then.  A bit of swap is
used and free memory is kind of low.  In my case the culprit seems to be
ARC.

last pid: 28589;  load averages:  1.06,  1.09,  1.08    up 3+15:55:10  16:12:51
71 processes:  2 running, 63 sleeping, 6 stopped
CPU:  7.0% user,  0.0% nice,  0.9% system,  0.0% interrupt, 92.1% idle
Mem: 564M Active, 6787M Inact, 23G Wired, 277M Buf, 656M Free
ARC: 16G Total, 5494M MFU, 2062M MRU, 499K Anon, 573M Header, 8434M Other
Swap: 40G Total, 4108K Used, 40G Free

When I'm making heavy use of poudriere, swap usage goes up a lot and the
pressure on free memory decreases the ARC size significantly.

It's a headless machine accessed via ssh, so I won't see any issues with
Xorgs and its clients getting paged out.  Remote shell access seems to
perform ok for me.

Before r297203 I was running r296416 and really pushed it hard.  I
didn't observe any unexpected interactivity issues even with more than
10G of swap used and a load average over 50.  I'd love to add more RAM,
but the motherboard is at max capacity.

The problems that some are describing sound a lot like lost interrupts
or lost wakeups.  The former could easily be hardware dependant.

My FreeBSD 10.3-PRERELEASE desktop is worse under load.  It also uses
zfs, but only has 8 GB of RAM.  The main culprit is firefox, which gets
very bloated after a while.  I've got some other hoggish processes on
it, which doesn't help.