LAM/MPI General User's Mailing List Archives

From: Ming Wu (wuming_at_[hidden])
Date: 2004-03-29 13:47:25

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• Reply: Roberto Pasianot: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Reply: dburbano_at_[hidden]: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Maybe reply: Ming Wu: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Maybe reply: Ming Wu: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Reply: Neil Storer: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"

Hi,

I assigned multiple processes on one machine instead of several machines. In this way, I expect the communication cost will be reduced compared with assigning them to several machines. However, the result is weird. both computation cost and communication cost are increased sharply, especially MPI_Reduce, MPI_Sendrecv. It seems that the underlying implementation of lam_mpi doesn't favor multiple processes on the same host.

Your help will be greatly appreciated.

thanks

• Next message: Roberto Pasianot: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Previous message: Jeff Squyres: "Re: LAM: Please help me!"
• Next in thread: Roberto Pasianot: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Reply: Roberto Pasianot: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Reply: dburbano_at_[hidden]: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Maybe reply: Ming Wu: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Maybe reply: Ming Wu: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"
• Reply: Neil Storer: "Re: LAM: is that possible to reduce the communication cost by assigning processes on the same node"