Bug#567056: brasero: Brasero is very slow burning a data DVD-R

[Thomas Schmitt]

Hi,

> I'm sorry, I'm running a home mail server using a dynamic IP address

Your mails are marked as "spam" but i do not
allow my mail provider's automat to drop any
mails.

I now got the two missing mails
  Date: Mon, 8 Feb 2010 15:14:58 -0300
  Date: Mon, 8 Feb 2010 15:16:11 -0300
just together with your newest mail
  Date: Thu, 11 Feb 2010 21:11:35 -0300
The culprit seems to be
  host33.190-230-6.telecom.net.ar
which sat on the mails since monday,
according to "Received:" headers.
(Your own machine ?)


> > If Brasero can burn to a disk file as "drive"
> > target, then try whether it is as slow

> Yes, it does. It took about 4.5 minutes to build a 4.4GB image.

That's about 16 MB/s = 12 x DVD speed.

Not overly fast but no reason to slow down
burning to 2.5 DVD speed.


> But it seems like Brasero uses growisofs, and AFAIK growisofs doesn't use
> libisoburn to make the image, right?

The proposed xorriso commands would do a similar
run as Brasero did with the disk file as "drive".
The data would flow through an interface object
between libisofs and libburn. libburn would
forward them to the fastest known consumer:
/dev/null.
I.e. the gathering of input data and production
of the ISO image stream would be the same as
in Brasero. The further data processing would
not.

It might be that this experiment becomes
necessary if there cannot be found a reason why
Brasero produces its ISO image at >= 12x speed
but hands it over to growisofs at only 2.5.


So, now we should ask the brasero developers
whether they have an idea what could be the
bottleneck between libisofs and growisofs.

If there is no insight emerging, then you should
make a xorriso dummy run on DVD-R.
Maybe we are "lucky" by seeing a similarly bad
performance. Then i would have a jacking point
for own examinations.


Have a nice day :)

Thomas