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Date: Fri, 21 Mar 2008 11:42:30 -0700
From: Julian Elischer <julian@elischer.org>
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To: Barney Cordoba <barney_cordoba@yahoo.com>
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Cc: current@freebsd.org
Subject: Re: kvm_read() vs ioctl performance
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Barney Cordoba wrote:
> I have an app which reads stats from the kernel
> periodically, and there can be a lot of iterations,
> sometimes 20,000 or more. I'm thinking of converting
> from an ioctl method to kvm_read(). KVM is certainly
> simpler, but its not clear what overhead is involved,
> since kvm_read() likely has to call the kernel also.
> 
> Does anyone have a handle on the difference in
> overhead, assuming that the ioctl call is to a module
> which does nothing more than copy the data and return?

tried a shared memory page?

> 
> Thanks,
> 
> barney
> 
> 
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