Subject: Re: Preparing callout(9) for a HZ-less kernel
To: Joerg Sonnenberger <>
From: Jason Thorpe <>
List: tech-kern
Date: 10/23/2007 08:47:28
On Oct 23, 2007, at 5:10 AM, Joerg Sonnenberger wrote:

> For callout_stop, I would expect it to be a relative rare operation,  
> so
> optimising that doesn't matter. callout_reset/callout_schedule  
> happens a
> lot more often, but I don't think it is performance critical either.  
> It
> happens a lot to extend the trigger period and it should be analyzed  
> if
> a lazy update of the tree is more efficient. I doubt it though.

callout_stop() is actually a fairly frequent operation.  It's used to  
detect timeouts on I/O operations for e.g. SCSI and ATA commands.

-- thorpej