ZFS txg implementation flaw

[Jordan Hubbard]

On Oct 28, 2013, at 2:28 AM, Slawa Olhovchenkov <slw at zxy.spb.ru> wrote:

> As I see ZFS cretate seperate thread for earch txg writing.
> Also for writing to L2ARC.
> As result -- up to several thousands threads created and destoyed per
> second. And hundreds thousands page allocations, zeroing, maping
> unmaping and freeing per seconds. Very high overhead.

How are you measuring the number of threads being created / destroyed?   This claim seems erroneous given how the ZFS thread pool mechanism actually works (and yes, there are thread pools already).

It would be helpful to both see your measurement methodology and the workload you are using in your tests.

- Jordan