On Tue, Oct 29, 2002 at 11:53:45AM -0500, Gianni Johansson wrote:
> The new load balancing code is a very good thing indeed, but I doubt it will
> save individual nodes from massive overload.
>
> Has anyone conclusively figured out the CPU usage issue?
I had high CPU usage yesterday when the node was overloaded, but nothing
to indicate runaway 100% usage. The dump you sent me didn't contain any
giveaways either.
Is it a single thread that is using all the CPU when this happens to
you?
> I suspect that there might have been a regression somewhere between 600 and
> 603, however, it is impossible to test on the public network under the
> present conditions.
It's always possible, but no particularly dangerous code went in during
that interval.
> Also, it seems like we need some mechanism to shut down the node under
> massive overload ("Seppuku mode"?). I doubt that my PII 233 node was doing
> much for the network as the the inbound connection rate exceeded 30K an hour
> and the load average hovered around 70.
I agree about this. I took my node offline for 12 hours last night
because I figured it was doing more harm then good, and brought it back
up midday today. It is now working well again.
A clean TCP connection refused will be a lot faster then setting up a
TCP connection and then closing it - so it is desireable on both ends.
It needn't be very difficult to do either - just make
freenet.interface.PublicInterface shut down completely if it rejects too
many connections over some period.
The only issue with this is, of course, that the node will be completely
unusable even for local requests. But that is the case when it is
severly overloaded too...
> I don't understand why my node keeps trying to process requests.
> It used to be that the node would just stop accepting connections when the
> number of threads exceeded some ridiculous number. Is that code still there?
> Also is the number of threads still used to decide when to reject requests?
It is still there - the diagnostics showed that my node was rejecting
4/5 incoming connections yesterday.
> Finally what about rate limiting Announcement requests? Aren't announcements
> quite expensive for the node to process?
It's probably not that significant.
--
Oskar Sandberg
oskar at freenetproject.org
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