Does Ext4 support parallel write similar to XFS?

[Amit Sahrawat]

In XFS we can write parallel (i.,e we can make use of allocation
groups for writing process). If the files are kept in individual
directories, there is a possibility that first the blocks for that
files be used from individual allocation groups. If I start ‘4’
writing process(cp 100MB_file /<dirnum>/) – after writing is finished
– if I check the bmap – it does shows that initial allocation was from
individual allocation groups.
Even though in Ext4 also we do have groups – but I am not able to get
behavior similar to XFS.
If I check the file extents – the extents are in mixed form, the
allocation pattern is also very fragmented.

Please share more on this. Also, if there is a possible exact test
case to check for parallel writes support.

Thanks & Regards,
Amit Sahrawat