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

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



Rob Bogus <rob23@tmr.com> wrote:

> I'm attaching a tiny program to show that isn't the case. It's for 
> zeroing out large files. If you have a disk intensive application you 
> might run this to zero out say 50GB or so, and compare the impact on the 
> application with dd of /dev/zero using 1024k buffer size. The program 
> has compiled on rh7.2 thru FC4, SuSE, ubuntu, etc, no kernel headers or 
> GNU needed, you want the POSIX behaviour, or at least I do.

Your program is not POSIX as it uses O_DIRECT and posix_memalign()
(the first is no POSIX at all, the latter is optional.....).

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

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

Jörg

-- 
 EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
       js@cs.tu-berlin.de                (uni)  
       schilling@fokus.fraunhofer.de     (work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily



Reply to: