Mitigations/tunables for reducing netlink loss?

[Dave Johnson]

Thanks all,

I increased the system-wide default to 2MB and seems to be better
(default was 256K).

On code changes, I completely agree this should be configurable either
globally or per protocol kernel, having to set a system-wide default
when a socket option is available isn't great.

On the previously posted patch, I don't think SO_RCVBUFFORCE would be
the best idea.  Generally, max system setting should be honored, and
SO_RCVBUF used (caped at the lesser of user configured value and the
system-wide max).


Alexander writes:
> On 2021-09-21 17:51, Trisha Biswas wrote:
> 
> > We are using the following patch to increase the netlink receive
> > buffer size to 2 MB.
> 
> I am afraid that this might be insufficient - as it depends on CPU 
> power,
> system load and probably some other factors like number of routes etc.
> 
> In my case (multi-CPU dedicated border router) where bird is the only 
> significant
> consumer of CPU power and running only BGP (with very few OSPF nodes)
> I had to set it to 128MB to get rid of any loss, 64MB was barely 
> sufficient.
> 
> Therefore I believe it makes sense to make the buffer size configurable.
> 
> /Al

-- 
Dave