[MITgcm-devel] local (tiled) MDSIO

[Jean-Michel Campin]

Hi Martin,

I've check-in a modification to MDSIO pkg such as tiled IO are
now done by chunk of 1-level tile (instead of 1-line of length sNx).
I remember you reported that non-SingleCpuIO was slower than
SingleCpuIO because of many small read/write pieces. 
This modification should improve the speed of those IO,
and it would be interesting to see if it really does (because it's
still a matter of platform/disk system ...).

I've did some short test with lot of IO, and in the most favorable one
(verification/deep_anelastic), without any Optimisation, I get:
 std_outp.new   User: 13.3799661 System: 0.490924996 Wall clock: 14.110111
 std_outp.ref   User: 15.7935989 System: 6.53900592 Wall clock: 22.7398989
In other cases, I've seen also a reduction of the System time,
but the wall-clock time improvement was not as big.

Cheers,
Jean-Michel