Re: BUG: Slowdown on 3000 socket-machines tracked down

From: Christian Schmid
Date: Fri Mar 11 2005 - 10:31:59 EST


I admit, totally coincidentially but its really FIXED. Today I went to the puter scanning the servers by routine and wondered why the bandwidth is at 100% without any holes.

The only thing I have done is I switched off hyper-threading because the server is at only 20% CPU anyway so I just disabled it.

So its something with linux dealing with hyper-threading. YAY :)

Andrew Morton wrote:
Christian Schmid <webmaster@xxxxxxxxxxxxxx> wrote:

> So, maybe a VM problem? That would be a good place to focus since
> I think we can be fairly certain it isn't a problem in just the
> networking code. Otherwise, my tests would show lower bandwidth.

Thanks to your tests I am really sure that its no network-code problem anymore. But what I THINK it is: The network is allocating buffers dynamically and if the vm doesnt provide that buffers fast enough, it locks as well.

Did anyone have a 100-liner which demonstrates this problem?

The output of `vmstat 1' when the thing starts happening would be interesting.

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