Newsgroups: comp.parallel.mpi From: "Umesh Kumar V. Rajasekaran" Subject: Re: any difference in installing MPICH 1.1 in user space and kernel space Organization: ECECS Department, University of Cincinnati, http://www.ececs.uc.edu/ Date: Mon, 02 Mar 1998 11:57:57 -0500 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <34FAE515.28C0F38@ececs.uc.edu> I checked the time taken by the MPI routines particularly MPI_Isend routine. I tried tracing the time for all the packets for about 100 packets. of size 128bytes. In Sun machine, sparc5. the routine takes on the average 2000 microseconds, the average calculated for 100 packets. Each MPI_Isend takes from 1900 - 2100 microseconds. In Linux the routine takes on the average 4100 microseconds, the average calculated for 100 packets. For every 5 MPI_Isend, the first four MPI_Isend takes around 200 microseconds. and the fifth one takes around 20000 microseconds. This is what I observed. Can anybody give explanation for this. Will it be due to TCP overhead which is varying here. It is just sparc Station 5. It is not HyperSparc inside thanks, -- Umesh Kumar V. Rajasekaran Department of Electrical and Computer Science and Computer Engineering University of Cincinnati email: urajasek@ececs.uc.edu URL: http://www.ececs.uc.edu/~urajasek/