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List:       openbsd-tech
Subject:    Re: Software interrupts in OpenBSD
From:       Ted Unangst <tedu () zeitbombe ! org>
Date:       2005-08-23 2:45:44
Message-ID: Pine.BSO.4.61.0508222242320.12551 () af ! pbqrshfvbavf ! pbz
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On Mon, 22 Aug 2005, Bijoy Thomas wrote:

> Can you tell me where in the kernel sources this code is?Also, what is
> the difference between splnet and splsoftnet? 

arch/  for i386, code is under sys/arch/i386/i386 and sys/arch/i386/isa.  
splnet is the interrupt level of hardware nics.  softnet is for the top 
half.

any code which touches data that may be modified by a network has to use 
splnet.  syscalls that touch network data use splsoftnet to prevent the 
software interrupt from running after a hardware interrupt, but without 
blocking the hardware interrupt.


-- 
And that's why it doesn't affect the engine performance.

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