Re: [Nbd] strange delay of 5ms

[Wouter Verhelst <w@...112...>]

On Fri, Apr 22, 2011 at 02:31:23PM +0200, folkert wrote:
> Hi,
> 
> I noticed something odd:
> 
> for(;;) {
> 
> 	// get timestamp in ms start
> 
> 	read(fd, size_of_nbd_request)
> 
> 	// get timestamp in ms end
> 
> 	printf("delay: %f\n", end - start);
> 
> 	// process request
> }
> 
> Then, on a localhost-connection with:
> dd if=/dev/zero of=/dev/nbd0
> 
> in this setup I noticed that it takes 5ms for the request header to come
> in, but only when the processing takes a while.
> What can be the cause of this?

I'm not sure. I'm aware that nbd-server performance isn't exactly
perfect, and I plan on working on that, but it would involve some
significant work.

-- 
The volume of a pizza of thickness a and radius z can be described by
the following formula:

pi zz a