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Re: [PATCH]: e1000: prevent statistics from getting garbled during rese

Subject: Re: [PATCH]: e1000: prevent statistics from getting garbled during reset.
From: "Jeff V. Merkey"
Date: Fri, 31 Mar 2006 20:01:01 +0200
Newsgroups: linux.kernel
Linas Vepstas wrote:

On Thu, Mar 30, 2006 at 09:14:56PM -0700, Jeffrey V. Merkey wrote:
Yes, we need one. The adapter needs to maintain these stats from the
registers in the kernel structure and not
its own local variables.

Did you read the code to see what the adapter does with these stats? Among other things, it uses them to adaptively modulate transmit rates to avoid collisions. Just clearing the hardware-private stats will mess
up that function.

I noticed that.

That way, when someone calls to clear the stats
for testing and analysis purposes,
they zero out and are reset.

1) ifdown/ifup is guarenteed to to clear things. Try that.
No, not dynamic. I'll patch the driver locally, thanks.

Jeff

2) What's wrong with taking deltas? Typical through-put performance
measurement is done by pre-loading the pipes (i.e. running for
a few minutes wihtout measuring, then starting the measurement).
I'd think that snapshotting the numbers would be easier, and is trivially doable in user-space. I guess I don't understand why you need a new kernel featre to imlement this.

--linas


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