performance question - Sun Fire X2100 M2
Hello, we are using Sun Fire X2100 M2 with dual-core Opteron processor. I have two simple questions:
Two applications are running parallel and want access memory at the same time (different memory cells). Does architecture support this simultaneous operation or access to memory is sequential. I know that CPU has build-in memory controller but it is not clear how this kind of operation is handled.
Second question is very similar just with InfiniBand card. Two applications want send data over InfiniBand. Is it possible to send data simultaneously or just by one-by-one approach.
Thanks for any info. Michal
[635 byte] By [
brundibara] at [2007-11-27 1:51:45]
# 1
Both cores of the dual core CPU have a memory controller, and the motherboard is laid out so that each core has a primary memory section that is accessed first, although any one core can access all memory if process size becomes larger than the core's primary memory size.
For infiniband, it is a bus based interface, so the process writing data must reserve the bus, do its transfer, and free the bus. So it is, as you say, a one-one approach, as all bus architectures are.
On our infiniband cluster, we find about a 30% increase in process speed vs. gigabit ethernet on heavy I/O bound applications. This is due to the lower latency of the IB interface. While IB is 10Gb, our applications are not bandwidth limited, but packet bound (typically 2-3mpps per port).
