Re: [Bug-tar] a multithreaded tar ??

[Dr. David Alan Gilbert]

Joerg Schilling wrote:
> Don Lindsay <address@hidden> wrote:
> >
> > Is anyone working on this?
> >
> > Now that multicore chips are everywhere, it seems like a worthwhile 
> > feature. I did some crude measurements on a 4P box and saw the potential 
> > for a decent speedup. [Specifically, untar of a .gz wasn't bottlenecked on 
> > IO.]
> 
> What do you like to achive here and on which OS?
> 
> star runs as two processes since 12 years, an archive I/O process and a 
> file I/O process.

I've been thinking a multithreaded tar would be nice for traversing
the directory trees in parallel; if you have a very big directory
tree with zillions of small files a single threaded tar ends up
I assume spending most of its time waiting for the OS to stat and open
files and the disc head to whizz back and forward.

If you had a multithreaded tar then you could have multiple outstanding
open's and stat's and directory reading with the OS and it could
have a chance to order them for least head movement.

Dave
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