In message from Håkon Bugge <[EMAIL PROTECTED]> (Thu, 26 Jun 2008
11:16:17 +0200):
Numastat statistics before Gaussian-03 run (OpenMP, 8 threads, 8
cores,
requires 512 Mbytes shared memory plus something more, may be fitted
in memory of any node - I have 8 GB per node, 6- GB free in node0 and
7+ GB free in node1)
node0:
numa_hit 14594588
numa_miss 0
numa_foreign 0
interleave_hit 14587
local_node 14470168
other_node 124420
node1:
numa_hit 11743071
numa_miss 0
numa_foreign 0
interleave_hit 14584
local_node 11727424
other_node 15647
-------------------------------------------
Statistics after run:
node0:
numa_hit 15466972
numa_miss 0
numa_foreign 0
interleave_hit 14587
local_node 15342552
other_node 124420
node1:
numa_hit 12960452
numa_miss 0
numa_foreign 0
interleave_hit 14584
local_node 12944805
other_node 15647
-------------------------------------------
Unfortunately I don't know, what exactly means this lines !! :-(
(BTW, do somebody know ?!)
But intuitive it looks (taking into account the increase of
numa_hit and local_node values), that the allocation of RAM was
performed from BOTH nodes (and more RAM was allocated from node1
memory - node1 had initially more free RAM).
It is in opposition w/my expectations of "continuous" RAM allocation
from the RAM of one node !
Mikhail Kuzminsky,
Computer Assistance to Chemical Research
Zelinsky Institute of Organic Chemistry
Moscow
At 18:34 25.06.2008, Mikhail Kuzminsky wrote:
Let me assume now the following situation. I have OpenMP-parallelized
application which have the number of processes equal to number of CPU
cores per server. And let me assume that this application uses not
too more virtual memory, so all the real memory used may be placed in
RAM of *one* node.
It's not the abstract question - a lot of Gaussian-03 jobs we have
fit to this situation, and all the 8 cores for dual socket quad core
Opteron server will be "well loaded".
Is it right that all the application memory (w/o using of numactl)
will be allocated (by Linux kernel) in *one* node ?
Guess the answer is, it depends. The memory will be allocated on the
node where the thread first touching it is running. But you could use
numastat to investigate the issue.
Håkon
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