ZFS txg implementation flaw

[aurfalien]

On Oct 28, 2013, at 2:28 AM, Slawa Olhovchenkov wrote:

> I can be wrong.
> 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.
> 
> In systat -vmstat I see totfr up to 600000, prcfr up to 200000.
> 
> Estimated overhead -- 30% of system time.
> 
> Can anybody implement thread and page pool for txg?

Would lowering vfs.zfs.txg.timeout be a way to tame or mitigate this?

- aurf