On Wed, 11 Jul 2012, Joerg Schilling wrote:

Bob Friesenhahn <bfrie...@simple.dallas.tx.us> wrote:

On Tue, 10 Jul 2012, Edward Ned Harvey wrote:

CPU's are not getting much faster.  But IO is definitely getting faster.  It's 
best to keep ahead of that curve.

It seems that per-socket CPU performance is doubling every year.
That seems like faster to me.

This would only apply, if you implement a multi threaded hash.

While it is true that the per-block hash latency does not improve much with new CPUs (and may even regress), given multiple I/Os at once, hashes may be be computed by different cores and so it seems that total system performance will scale with per-socket CPU performance. Even with a single stream of I/O, multiple zfs blocks will be read or written so mutiple block hashes may be computed at once on different cores.

Server OSs like Solaris have been focusing on improving total system throughput rather than single-threaded bandwidth.

I don't mean to discount the importance of this effort though.

Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
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