[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: dvd+rw-tools update [6.0, DVD-R DL]

Joerg Schilling wrote:

Bill Davidsen <davidsen@tmr.com> wrote:

But now I see where you like to use O_DIRECT.

If you use O_DIRECT for writing, it makes sense and in the same case
it makes sense to use directio(fd, DIRECTIO_ON); on Solaris.

By not buffering the output of mkisofs, for example, buffer space is available for reading. This makes a small improvement on a large memory, much more as the memory is smaller and read ahead could be impacted by buffering writes.

Although on Solaris, it only saves System CPU time and I cannot see
an wall clock improvement.

I haven't tested there, and I bet you have not tested in small memory (I use 160MB for test).

Whether this makes sense with the _output_ file from star or mkisofs
needs to be tested.....

I had not tried with the output of star, that's an interesting suggestion.

I did try it recently with creating a SchilliX ISO image (~ 20000 files
700 MB) and it did not help.

Did you do the test on a machine with limited memory? I may have asked this before, but I don't see a reply, sorry if this is a repeated question. I find the great benefit when memory for buffers is limited.

Thanks for testing.

bill davidsen <davidsen@tmr.com>
 CTO TMR Associates, Inc
 Doing interesting things with small computers since 1979

Reply to: