Speed problem

jw schultz jw at pegasys.ws
Thu Nov 14 20:27:00 EST 2002

On Thu, Nov 14, 2002 at 09:44:45PM +1100, Donovan Baarda wrote:
> On Wed, Nov 13, 2002 at 02:17:28AM -0800, jw schultz wrote:
> > While the receiver bears the brunt of the CPU work the
> > sender is hardly idle.  Aside from generating the initial
> The reciever _doesn't_ bear the brunt of the CPU work, the sender does.
> Unless something very drastic has been changed in rsync in the last 2
> months, the sender has to calculate the delta from a signature sent by the
> reciever. Delta calculation is _heaps_ more CPU intensive than signature
> calculation.

Thanks.  That's twice now i've reversed it.  50-50 and i get
it wrong like Franklin but with no excuse. 

Have to remember to follow the process flow. Not observed
behavior on asymetrical boxes nor what would be wanted for a

> > You may want to read the whitepaper.
> hmmm... methinks you might have muddled the white-paper yourself :-)

You are right, it may be time to review it again.

> I'm not exactly sure how the sender/reciever negotiate the include/exclude
> file lists, but it is the _receiver_ that most certainly calculates and
> sends the block checksums, and the _sender_ performs the rolling checksum
> delta calculation to identify any matches, sending a sequence of match
> details and missed data to the reciever.

Anyway, thanks for correcting me.

	J.W. Schultz            Pegasystems Technologies
	email address:		jw at pegasys.ws

		Remember Cernan and Schmitt

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