W*****d
发帖数: 4196 | | w******u
发帖数: 5 | 2 Here is what Zen's operator said a while back: http://computer-go.computer-go.narkive.com/ZURj9hBS/a-cluster-version-of-zen-is-running-on-cgos-19x19
Post by Hideki Kato
Also, on 19x19 board, current 16-core cluster version performs almost
the same as 8-core shared memory pc such as Mac Pro, which Yamato used
for KGS.
Hi Hideki,
Is that difference due to a scaling limit of Zen, or is this due to the
cluster overhead? Would moving from gigabit to infiniband help, or is
the limit more to do with the lack of shared memory?
Post by Hideki Kato
I'm right now evaluating the scaling (:-).
The performance gap is perhaps due to the algorithms. Almost all
cluster versions of current strong programs (MoGo, MFG, Fuego and Zen)
use root parallel while shared memory computers allow us to use thread
parallelism, which gives better performance. The main reason, I
guess, is that the latter increses the depth of the search tree
according to the number of processors (cores) while the former does
not.
One interesting observed thing of root parallel is that the scaling
depends on the time for a move; longer time setting shows better
scalability, when the time period to exchange root information is
fixed. In other words, each time setting has its best number of
nodes. This makes things complicated :(.
The scaling limit of Zen is still unknown, though I expected that the
playouts of Zen was not so random that it did not scale well, before
starting this joint project with Yamato. | n*******s
发帖数: 17267 | 3 缺很多东西，打劫不说，基本就是一根筋，要胜高手路漫漫啊。 |
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