Key for high CPU usage

Leen Besselink leen at
Thu Jun 11 06:08:13 GMT 2009

Daniel.Li wrote:
> Dear List,
> I'm trying to take a closer look at rsync code, and found when we run
> daemon, it will take a lot of CPU (400Mhz). So I'm interested in Which
> part of rsync code on ver 3.0.5 consuming CPU a lot?
> Can anyone here help to lighten me up? So I can try to improve the
> performance or low the CPU usage.
> I suspect that there are a few factors, which might related with CPU
> usage: rolling checksum/Disk IO(a slide window has been implemented),
> read or write?
> Hope I can find some info here! Thanks in advance! 

Hi Daniel,

Not sure how much you know about how rsync works, but maybe you first want
to know how the algoritm works ? I'm fairly sure it's a large part of the

But I personally enjoyed the talk talk Andrew Tridgell did at OLS in 2000
more, here is a transcript:

Here are the slides of the talk:

I wouldn't be surprised if you were able to find the mp3 online somehere
with the filename:


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