I got the point. All three nodes are both data servers and clients. So results in "Group 6" case are expected too. Thank you very much.
-- Hamza On 11/23/05, Rob Ross <[EMAIL PROTECTED]> wrote: > Hi Hamza, > > Running extra I/O applications on the same node is going to result in > decreased apparent performance for each process: you're doing N times as > much with with the same client and network connection. The CPU > scheduler gives each one a fair share of time, so they all end up > getting the processor 1/Nth of the time and so take roughly N times as long. > > For the multi-node cases, you did get a performance increase overall in > the "Group 2" case. Three processes wrote data in about the time it > would have taken two to write if they had done so on one processor. > Likewise for reading in "Group 6" case. > > Are you using nodes as both servers and clients? > > Thanks, > > Rob > > Hamza KAYA wrote: > > When I tried on different machines I got better results but again > > worse than one execution. Results are given below. So file access > > performances decrease linearly with the number of accesses. Is there a > > configuration that will make pvfs2 scale better for concurrent > > accesses? Why pvfs2 behave like this? > > > > -- GROUP - 1--- > > time -p ./write /pvfs2/t1 100 => 26.44 [executed on master] > > time -p ./write /pvfs2/t2 100 => 26.72 [executed on master] > > time -p ./write /pvfs2/t3 100 => 26.57 [executed on master] > > > > --- GROUP - 2--- > > time -p ./write /pvfs2/t4 100 => 17.69 [executed on node1] > > time -p ./write /pvfs2/t5 100 => 17.55 [executed on node2] > > time -p ./write /pvfs2/t6 100 => 16.91 [executed on node3] > > > > --- GROUP - 3--- > > time -p ./write /pvfs2/t7 100 => 9.42 [executed on master] > > > > --- GROUP - 4--- > > time -p ./write /pvfs2/t8 100 => 9.12 [executed on node1] > > > > --- GROUP - 5--- > > time -p ./read /pvfs2/t4 ./t4 => 26.17 [executed on master] > > time -p ./read /pvfs2/t5 ./t5 => 27.00 [executed on master] > > time -p ./read /pvfs2/t6 ./t6 => 26.92 [executed on master] > > > > --- GROUP - 6--- > > time -p ./read /pvfs2/t4 ./t4 => 14.64 [executed on node1] > > time -p ./read /pvfs2/t5 ./t5 => 16.62 [executed on node2] > > time -p ./read /pvfs2/t6 ./t6 => 15.55 [executed on node3] > > > > --- GROUP - 7--- > > time -p ./read /pvfs2/t4 ./t4 => 9.89 [executed on master] > > > > --- GROUP - 8--- > > time -p ./read /pvfs2/t4 ./t4 => 10.02 [executed on node1] > > > > > > On 11/22/05, Rob Ross <[EMAIL PROTECTED]> wrote: > > > >>The numbers make absolute sense for four executions on the same machine. > >> > >>Rob > >> > >>Hamza KAYA wrote: > >> > >>>Yes. I'll try them on different machines too. I'll inform you as soon > >>>as possible. > >>>Thanks very much. > >>> > >>>-- > >>>Hamza > >>> > >>>On 11/21/05, Rob Ross <[EMAIL PROTECTED]> wrote: > >>> > >>> > >>>>Hi, > >>>> > >>>>Are you running all those processes on the same machine? > >>>> > >>>>Rob > >>>> > >>>>Hamza KAYA wrote: > >>>> > >>>> > >>>>>Thanks very much. Another problem I observed is about simultaneous > >>>>>accesses. Normally a copying a 100MB file to pvfs takes approximately > >>>>>10secs. in my system. > >>>>> > >>>>>time -p ./copy testfile /pvfs2/testfile -> 9.76sec. > >>>>> > >>>>>However copying 4 files simultaneously gives the following results: > >>>>>time -p ./copy testfile1 /pvfs2/testfile1 -> approx. 36sec. > >>>>>time -p ./copy testfile2 /pvfs2/testfile2 -> approx. 36sec. > >>>>>time -p ./copy testfile3 /pvfs2/testfile3 -> approx. 36sec. > >>>>>time -p ./copy testfile4 /pvfs2/testfile4 -> approx. 36sec. > >>>>> > >>>>>[here 'copy' is a programme which uses the system calls. However same > >>>>>result occurs while using coreutils 'cp' and a simple program which > >>>>>makes consecutive fread and fwrite calls.] > >>>>> > >>>>>All of the files used are 100MB. And most of the operations > >>>>>overlapped. Another point is the CPU consumption of pvfs2-client-co. > >>>>>When multiple accesses to one file occurs, it consumes approx. %40 of > >>>>>the CPU. > >>>>>e.g. > >>>>> cp /pvfs2/test test1 > >>>>> cp /pvfs2/test test2 > >>>>> cp /pvfs2/test test3 > >>>>> cp /pvfs2/test test4 > >>>>> > >>>>>What may be the problem? Or is this situation is a problem? > >>>>>Thanks, > >>>>> > >>>>>-- > >>>>>Hamza > >>>>> > >>>>>On 11/18/05, Robert Latham <[EMAIL PROTECTED]> wrote: > >>>>> > >>>>> > >>>>> > >>>>>>On Thu, Nov 17, 2005 at 05:08:45PM +0000, Number Cruncher wrote: > >>>>>> > >>>>>> > >>>>>> > >>>>>>>I noticed Rob's post at > >>>>>>>http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00068.html > >>>>>>>which discusses a patch to cp. Has this been accepted? Where can I get > >>>>>>>a > >>>>>>>copy (excuse the pun!) > >>>>>> > >>>>>>The attached patch, based largely on earlier efforts by Neill Miller, > >>>>>>to coreutils CVS will make copy behave better with pvfs2. > >>>>>>Unfortunately, this patch also modifies lib/Makefile.am, so you'll > >>>>>>need fairly recent versions of autotools/automake/autowhatever. It > >>>>>>should apply ok against coreutils-5.92 > >>>>>> > >>>>>>I don't know if this will make it into coreutils-6.0, but i'll keep > >>>>>>bugging the maintainers... > >>>>>> > >>>>>>==rob > >>>>>> > >>>>>>-- > >>>>>>Rob Latham > >>>>>>Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF > >>>>>>Argonne National Labs, IL USA B29D F333 664A 4280 315B > >>>>>> > >>>>>> > >>>>>>_______________________________________________ > >>>>>>PVFS2-users mailing list > >>>>>>[email protected] > >>>>>>http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> > >>>>>_______________________________________________ > >>>>>PVFS2-users mailing list > >>>>>[email protected] > >>>>>http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users > >>>>> > >>>> > > > _______________________________________________ PVFS2-users mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
