cpio to ext4 seems much slower than to ext2, ext3 or xfs

[Gene Czarcinski]

On Wednesday 11 November 2009 06:41:58 Farkas Levente wrote:
> On 11/11/2009 11:53 AM, Richard W.M. Jones wrote:
> > On Wed, Nov 11, 2009 at 10:14:21AM +0000, Richard W.M. Jones wrote:
> >>   echo input | time cpio --quiet -o -H newc > /path/to/fs/output
> >
> > Update: I found the -C option that lets me specify the blocksize, and
> > raising it to something sensible (65536) shows major improvements in
> > performance for all filesystems.
> >
> >   echo input | time cpio -C 65536 --quiet -o -H newc > /path/to/fs/output
> >
> >>   tmpfs      0.77 s    x 1.0
> >>   ext2       1.12 s    x 1.5
> >>   xfs        1.66 s    x 2.1
> >>   ext3       2.58 s    x 3.4
> >>   ext4       5.59 s    x 7.3    <----
> >
> > The new times are:
> >
> >   tmpfs     0.20 s    x 1.0
> >   ext2      0.30 s    x 1.5
> >   xfs       0.41 s    x 2.1
> >   ext3      0.57 s    x 2.9
> >   ext4      0.44 s    x 2.2
> 
> imho it's still a bug. wouldn't somehow rise the default or make the
> writes buffered or ... since the current situation is not correct.
> 
I am not sure if this is related or not ...

During the F12 development cycle, I have done a number of installs on both 
bare hardware and qemu-kvm guests.

In all cases, I have formatted the root ("/") partition as ext4.  I have 
noticed that formatting the partition for ext4 seems to take considerably more 
wall-clock time for ext4 partitions than my previous experience with ext3 
partitions.

I do not know if this is because ext4 "formatting" needs to do a lot more work 
than ext3 or if there is a performance issue.

Gene