Re: XFS_IOC_RESVSP64 versus XFS_IOC_ALLOCSP64 with multiple threads

[Sam Vaughan <sjv@xxxxxxx>]

On 14/11/2006, at 11:25 AM, Chris Wedgwood wrote:

> On Tue, Nov 14, 2006 at 11:04:17AM +1100, Sam Vaughan wrote:
>
> > Those extents are curiously uniform, all 32kB in size.
> O_SYNC writes?
I'm assuming from Stuart's original email that these files weren't  
written out with write(), but instead pre-allocated using allocsp:
> So, this would lead me to try XFS_IOC_ALLOCSP64 - which doesn't  
> have the
> "unwritten extents" warning that RESVSP64 does. However, with the two
> processes writing the files out, I get heavy fragmentation. Even  
> with a
> RESVSP followed by ALLOCSP I get the same result.