CURRENT slow and shaky network stability
Don Lewis
truckman at FreeBSD.org
Sat Mar 26 21:26:55 UTC 2016
On 26 Mar, Michael Butler wrote:
> -current is not great for interactive use at all. The strategy of
> pre-emptively dropping idle processes to swap is hurting .. big time.
>
> Compare inactive memory to swap in this example ..
>
> 110 processes: 1 running, 108 sleeping, 1 zombie
> CPU: 1.2% user, 0.0% nice, 4.3% system, 0.0% interrupt, 94.5% idle
> Mem: 474M Active, 1609M Inact, 764M Wired, 281M Buf, 119M Free
> Swap: 4096M Total, 917M Used, 3178M Free, 22% Inuse
>
> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU
> COMMAND
> 1819 imb 1 28 0 213M 11284K select 1 147:44 5.97%
> gkrellm
> 59238 imb 43 20 0 980M 424M select 0 10:07 1.92%
> firefox
>
> .. it shouldn't start randomly swapping out processes because they're
> used infrequently when there's more than enough RAM to spare ..
I don't know what changed, and probably something can use some tweaking,
but paging out idle processes isn't always the wrong thing to do. For
instance if I'm using poudriere to build a bunch of packages and its
heavy use of tmpfs is pushing the machine into many GB of swap usage, I
don't want interactive use like:
vi foo.c
cc foo.c
vi foo.c
to suffer because vi and cc have to be read in from a busy hard drive
each time while unused console getty and idle sshd processes in a bunch
of jails are still hanging on to memory even though they haven't
executed any instructions since shortly after the machine was booted
weeks ago.
> It also shows up when trying to reboot .. on all of my gear, 90 seconds
> of "fail-safe" time-out is no longer enough when a good proportion of
> daemons have been dropped onto swap and must be brought back in to flush
> their data segments :-(
That's a different and known problem. See:
<https://svnweb.freebsd.org/base/releng/10.3/bin/csh/config_p.h?revision=297204&view=markup>
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