Patch proposal: Speeding up ZFS writes

[Xin LI]

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Hi, Martin,

On 2010/08/21 07:11, Martin Matuska wrote:
> b) on the mid-term, I suggest this patch for head with MFC to stable/8
> after some reasonable time (1-2 months):
> http://people.freebsd.org/~mm/patches/zfs/zfs_metaslab.patch
[...]
> The patch in b) includes the following OpenSolaris onnv revisions:
> 10921 (very small part, metaslab.c)
> 11146 (main patch, applies almost cleanly)
> 11728 (fix for zdb.c)
> 12047 (improvement to metaslab.c)
> 
> OpenSolaris Bug IDs:
> 6826241 Sync write IOPS drops dramatically during TXG sync
> 6869229 zfs should switch to shiny new metaslabs more frequently
> 6917066 zfs block picking can be improved
> 6918420 zdb -m has issues printing metaslab statistics

I think we should integrate this.

The only thing I feel confusing about the change is that the part
imported from OpenSolaris onnv revision 10921 on metaslab.c in
metaslab_activate(), which adds a space_map_load_wait(sm), does not seem
to be really necessary (the later 11146 change just added a blank space
there) as the corresponding space_map_load() change that removed the
wait() call was not merged.  Or, did I missed something here?

Cheers,
- -- 
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!	       Live free or die
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