[mpich-discuss] Profiling configuration file mpe_mpilog.conf

[Anthony Chan]

Is 150 microseconds for one 0-byte message send-recv ?
If so, it is way too much.  Depending on your hardware,
the overhead should be of the microsecond range or less.  There
is a program <mpich2-install>/share/log_cost which is a serial
program which measures the logging cost.  You can run it
on your target machine and use jumpshot to see the logging
overhead.

In general, when you are doing latency/bandwidth measurement,
you don't want MPE logging.  As MPE logging will perturb
the memory usage of the measure program, some latency/bandwidth
measurements on certain hardware will be sensitive to this
perturbation.

A.Chan
----- "Krishna Chaitanya" <kris.c1986 at gmail.com> wrote:

> Just out of curiosity, I was trying to measure the overhead due the
> MPE component. For a message size of 0 bytes, averaged over 1000
> attempts, I noticed that the latency increases by about 150 micro s ,
> when compiled with the -mpe=mpilog switch, Is this expected?
> 
> 
> Thanks,
> Krishna Chaitanya K
> 
> 
> 
> On Sat, May 3, 2008 at 12:55 PM, Krishna Chaitanya <
> kris.c1986 at gmail.com > wrote:
> 
> 
> I think I figured it out. Its working now. Thanks.
> 
> 
> 
> 
> 
> On Sat, May 3, 2008 at 2:42 AM, Anthony Chan < chan at mcs.anl.gov >
> wrote:
> 
> 
> 
> 
> ----- "Krishna Chaitanya" < kris.c1986 at gmail.com > wrote:
> 
> > Hi,
> > I have made a few changes in the MPI source code and added a few
> lines
> > of code into the MPE module. To compile the cpi program in the
> > examples directory, I have added the -mpe=mpilog switch in the
> > makefile. It was working well until it started reporting this error
> :
> >
> > ../bin/mpicc -g -O2 -mpe=mpilog -L../lib -o cpi cpi.o -lm -lmpich
> > -lpthread -lrt
> 
> Assuming the mpicc that you invoked is in the mpich2 install
> directory,
> you don't need "-L../lib" and "-lmpich ...." which are already done
> in mpicc.
> 
> 
> > Profiling configuration file mpe_mpilog.conf not found in
> > /home/mpich-install/etc
> 
> Is there a mpe_mpilog.conf in /home/mpich-install/etc ?
> If not, your installation of MPE2 is broken.
> 
> 
> > This is followed by a few undefined references to the function that
> I
> > have added in the MPE module. I checked the messages displayed
> during
> > make and I noticed that the libmpe.a library was created
> successfully
> > at src/mpe2/lib. What could be the problem?
> 
> Send us your configure, make and "make install" output as shown on
> your screen.
> 
> A.Chan
> 
> 
> 
> 
> > Thanks,
> > Krishna Chaitanya,
> >
> >
> >
> > --
> > In the middle of difficulty, lies opportunity
> 
> 
> 
> 
> --
> 
> 
> 
> In the middle of difficulty, lies opportunity
> 
> 
> --
> In the middle of difficulty, lies opportunity