[mpich-discuss] MPI memory allocation.

Anatoly G anatolyrishon at gmail.com
Thu Dec 19 08:51:27 CST 2013 

Can you please remove comment from section
/*
        // swap tag & enter blocked recv
        MPI_Status stat;
        tags[slaveIdx] = (tags[slaveIdx] == TAG1) ? TAG2 : TAG1;
        MPI_Recv(RcvBufs[slaveIdx], BUF_SZ, MPI::CHAR, slaveRank, tags[
slaveIdx], MPI_COMM_WORLD, &stat);

        ++SlavesRcvIters[slaveIdx];
*/

And then run it.
Do you see memory allocation increase?

Regards,
Anatoly.


On Thu, Dec 19, 2013 at 4:29 PM, Pavan Balaji <balaji at mcs.anl.gov> wrote:

>
> I’m not sure what I should look for.  I ran the program and it completed
> fine.
>
>   — Pavan
>
> On Dec 19, 2013, at 7:16 PM, Anatoly G <anatolyrishon at gmail.com> wrote:
>
> > Good afternoon.
> > My program enters a lot to attached stack functions.
> > Can you please explain if it's ok?
> > Did you success to execute simulation from previous mail.
> > Did you see the memory raise when MPI_Recv not in comments?
> >
> > Regards,
> > Anatoly.
> >
> >
> > On Thu, Dec 12, 2013 at 9:36 PM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > Hi.
> > Finally, I got an additional info.
> > I build short simulation of my real application.
> >
> > The short description of real scenario.
> > I have Master + N slaves. Each slave sends to Master 2 types of messages:
> >       • constant length message with predefined fields (one of it's
> fields is length of second message).
> >       • second message - length of this message each time is different
> and passed in first message.
> > Master should use MPI_Irecv commands, in order to be tolerant to slaves
> failure (blocked MPI_Recv is blocking Master in the failure case).
> > Master executes MPI_Irecv to each slave with buffer size equal to the
> constant size of first message type. After receiving first type of message,
> Master allocates expected buffer for second message and performs receive
> too. This happens in endless loop for each slaves. I use MPI_Waitany to
> monitor all receives.
> > In order to separate messages Master & slaves use different tags (as
> ids) for first & second messages.
> >
> > Simulation description:
> > All passed buffers (first & second) have the same size.
> > Slave (SndSyncSlave) sends messages and swaps 2 tags between them (like
> 2 types of messages, but second one has constant size too).
> > Master routine (Rcv_WaitAny function) executes MPI_Irecv for first
> message, and after receive executes MPI_Irecv for the second one.
> >
> > In this scenario: 5 processes works fine, but if I execute 20 processes
> and remove comment from line "usleep(200000)"  I see 800 Mbit/s on network
> at the test beginning, but after 1-2 second network speed become
> 200-300Kbit/s and not increased back any more.
> >
> > If I add MPI_Recv block in Master (remove comment from "MPI_Recv" and
> line around) I see that Master starts increase memory as my real
> application, but again on 5 processes this not happens. This is scenario
> used in my real application.
> >
> > Command line: mpiexec.hydra -genvall -f MpiConfigMachines.txt
> -launcher=ssh -n 20 mpi_rcv_any_multithread 100000 1000000 out
> >
> > where
> > 100000 - number of sends from each slave
> > 1000000 - scale to separate input from each scale (used for debug only)
> > out - prefix of output file. Each process produce out_"rank".txt file.
> >
> > MpiConfigMachines.txt - configuration file for my computers, 2 computers
> back to back 1 Gbit/s network.
> >
> >
> > Can you please test this case, and give me yours suggestions.
> >
> > Thank you,
> > Anatoly.
> >
> >
> >
> > On Mon, Dec 9, 2013 at 9:55 PM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > Yes, I understand that. I"ll try to make my stand alone test closer to
> real application. Thank you.
> >
> >
> > On Mon, Dec 9, 2013 at 9:31 PM, Pavan Balaji <balaji at mcs.anl.gov> wrote:
> >
> > It sounds like MPICH is working correctly.  Without a test case, it’s
> unfortunately quite hard for us to even know what to look for.  It’s also
> possible that there’s a bug in your code which might be causing some bad
> behavior.
> >
> >   — Pavan
> >
> > On Dec 9, 2013, at 1:27 PM, Anatoly G <anatolyrishon at gmail.com> wrote:
> >
> > > Yes, I"m actually need Fault tolerance, and it was the main reason for
> choosing MPICH2. I use fault tolerance for unpredictable bugs in the
> future. My system should survive partially. But in the regular case I just
> need full performance. I"m suspect that I don't use MPI correctly, but on
> slow rate everything works fine. The fail caused by increasing rate of
> MPI_Isend or increasing data buffer size. I didn't find yet any strong
> dependence, only main stream.
> > >
> > > Unfortunately I have a complex system which has a number of threads in
> each process. Part of the threads use different communicators.
> > >
> > > I try to simulate the same MPI behavior in simple stand alone test,
> but stand alone test works fine. It shows a full network performance, when
> I slow down master (on stand alone test), all slaves are stopped too and
> are waiting for master to continue. Can I open any MPICH log to send you
> the results?
> > >
> > >
> > > On Mon, Dec 9, 2013 at 8:10 PM, Pavan Balaji <balaji at mcs.anl.gov>
> wrote:
> > >
> > > Do you actually need Fault Tolerance (one of your previous emails
> seemed to indicate that)?
> > >
> > > It sounds like there a bug in either your application or in the MPICH
> stack and you are trying to trace that down, and don’t really care about
> fault tolerance.  Is that a correct assessment?
> > >
> > > Do you have a simplified program that reproduces this error, that we
> can try?
> > >
> > >   — Pavan
> > >
> > > On Dec 9, 2013, at 11:44 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > >
> > > > No. Hardware is Ok. Master process  allocates memory (check with
> MemoryScape doesn't show any sufficient memory allocation in my code). Then
> network traffic become low, and then Master process crashes w/o saving core
> file. I have unlimited size of core files. The same fail (w/o core) I see
> when I call MPI_Abort, but I don't call it.
> > > >
> > > >
> > > > On Mon, Dec 9, 2013 at 7:28 PM, Wesley Bland <wbland at mcs.anl.gov>
> wrote:
> > > > Are you actually seeing hardware failure or is your code just
> crashing? It's odd that one specific process would fail so often in the
> same way if it were a hardware problem.
> > > >
> > > > Thanks,
> > > > Wesley
> > > >
> > > > On Dec 9, 2013, at 11:15 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > > >
> > > >> One more interesting fact. Each time I have a failure, the fails
> only master process, but slaves are still exists together with
> mpiexec.hydra. I thought that slaves should fail too, but slaves are live.
> > > >>
> > > >>
> > > >> On Mon, Dec 9, 2013 at 10:30 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > > >> I configure MPICH-3.1rc2 build w/o "so" files. But instead of
> MPICH2 & MPICH-3.0.4 I get so files. What should I change in configure line
> to link MPI with my application statically.
> > > >>
> > > >>
> > > >>
> > > >> On Mon, Dec 9, 2013 at 9:47 AM, Pavan Balaji <balaji at mcs.anl.gov>
> wrote:
> > > >>
> > > >> Can you try mpich-3.1rc2?  There were several fixes for this in
> this version and it’ll be good to try that out before we go digging too far
> into this.
> > > >>
> > > >>   — Pavan
> > > >>
> > > >> On Dec 9, 2013, at 1:46 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > > >>
> > > >> > With MPICH - 3.0.4 the situation repeated. It looks like MPI
> allocates memory for messages.
> > > >> > Can you please advice about scenario when MPI or may be TCP under
> MPI allocates memory due to high transfer rate?
> > > >> >
> > > >> >
> > > >> > On Mon, Dec 9, 2013 at 9:32 AM, Anatoly G <
> anatolyrishon at gmail.com> wrote:
> > > >> > Thank you very much.
> > > >> > Issend - is not so good, It can't support me Fault tolerance. If
> slave process fails, the master stall.
> > > >> > I tried mpich-3.0.4 with hydra-3.0.4 but my program which uses
> MPI Fault tolerance doesn't recognize failure of slave process, but
> recognizes failure with MPICH2. May be you can suggest solution?
> > > >> > I tried to use hydra from MPICH2 but link my program with MPICH3.
> This combination recognizes failures, but I"m not sure that such
> combination is stable enough.
> > > >> > Can you please advice?
> > > >> > Anatoly.
> > > >> >
> > > >> >
> > > >> >
> > > >> > On Sat, Dec 7, 2013 at 5:20 PM, Pavan Balaji <balaji at mcs.anl.gov>
> wrote:
> > > >> >
> > > >> > As much as I hate saying this — some people find it easier to
> think of it as “MPICH3”.
> > > >> >
> > > >> >   — Pavan
> > > >> >
> > > >> > On Dec 7, 2013, at 7:37 AM, Wesley Bland <wbland at mcs.anl.gov>
> wrote:
> > > >> >
> > > >> > > MPICH is just the new version of MPICH2. We renamed it when we
> went past version 3.0.
> > > >> > >
> > > >> > > On Dec 7, 2013, at 3:55 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > > >> > >
> > > >> > >> Ok. I"ll try both Issend, and next step to upgrade MPICH to
> 3.0.4.
> > > >> > >> I thought before that MPICH & MPICH2 are two different
> branches, when MPICH2 partially supports Fault tolerance, but MPICH not.
> Now I understand, that I was wrong and MPICH2 is just main version of MPICH.
> > > >> > >>
> > > >> > >> Thank you very much,
> > > >> > >> Anatoly.
> > > >> > >>
> > > >> > >>
> > > >> > >>
> > > >> > >> On Thu, Dec 5, 2013 at 11:01 PM, Rajeev Thakur <
> thakur at mcs.anl.gov> wrote:
> > > >> > >> The master is receiving too many incoming messages than it can
> match quickly enough with Irecvs. Try using MPI_Issend instead of MPI_Isend.
> > > >> > >>
> > > >> > >> Rajeev
> > > >> > >>
> > > >> > >> On Dec 5, 2013, at 2:58 AM, Anatoly G <anatolyrishon at gmail.com>
> wrote:
> > > >> > >>
> > > >> > >> > Hello.
> > > >> > >> > I"m using MPICH2 1.5.
> > > >> > >> > My system contains master and 16 slaves.
> > > >> > >> > System uses number of communicators.
> > > >> > >> > The single communicator used for below scenario:
> > > >> > >> > Each slave sends non-stop 2Kbyte data buffer using MPI_Isend
> and waits using MPI_Wait.
> > > >> > >> > Master starts with MPI_Irecv to each slave
> > > >> > >> > Then in endless loop:
> > > >> > >> > MPI_Waitany and MPI_Irecv on rank returned by MPI_Waitany.
> > > >> > >> >
> > > >> > >> > Another communicator used for broadcast communication
> (commands between master + slaves),
> > > >> > >> > but it's not used in parallel with previous communicator,
> > > >> > >> > only before or after data transfer.
> > > >> > >> >
> > > >> > >> > The system executed on two computers linked by 1Gbit/s
> Ethernet.
> > > >> > >> > Master executed on first computer, all slaves on other one.
> > > >> > >> > Network traffic is ~800Mbit/s.
> > > >> > >> >
> > > >> > >> > After 1-2 minutes of execution, master process starts to
> increase it's memory allocation and network traffic becomes low.
> > > >> > >> > This memory allocation & network traffic slow down continues
> until fail of MPI,
> > > >> > >> > without core file save.
> > > >> > >> > My program doesn't allocate memory. Can you please explain
> this behaviour.
> > > >> > >> > How can I cause MPI to stop sending slaves if Master can't
> serve such traffic, instead of memory allocation and fail?
> > > >> > >> >
> > > >> > >> >
> > > >> > >> > Thank you,
> > > >> > >> > Anatoly.
> > > >> > >> >
> > > >> > >> > P.S.
> > > >> > >> > On my stand alone test, I simulate similar behaviour, but
> with single thread on each process (master & hosts).
> > > >> > >> > When I start stand alone test, master stops slaves until it
> completes accumulated data processing and MPI doesn't increase memory
> allocation.
> > > >> > >> > When Master is free slaves continue to send data.
> > > >> > >> > _______________________________________________
> > > >> > >> > discuss mailing list     discuss at mpich.org
> > > >> > >> > To manage subscription options or unsubscribe:
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> > > >> > >>
> > > >> > >> _______________________________________________
> > > >> > >> discuss mailing list     discuss at mpich.org
> > > >> > >> To manage subscription options or unsubscribe:
> > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss
> > > >> > >>
> > > >> > >> _______________________________________________
> > > >> > >> discuss mailing list     discuss at mpich.org
> > > >> > >> To manage subscription options or unsubscribe:
> > > >> > >> https://lists.mpich.org/mailman/listinfo/discuss
> > > >> > > _______________________________________________
> > > >> > > discuss mailing list     discuss at mpich.org
> > > >> > > To manage subscription options or unsubscribe:
> > > >> > > https://lists.mpich.org/mailman/listinfo/discuss
> > > >> >
> > > >> > --
> > > >> > Pavan Balaji
> > > >> > http://www.mcs.anl.gov/~balaji
> > > >> >
> > > >> > _______________________________________________
> > > >> > discuss mailing list     discuss at mpich.org
> > > >> > To manage subscription options or unsubscribe:
> > > >> > https://lists.mpich.org/mailman/listinfo/discuss
> > > >> >
> > > >> >
> > > >> > _______________________________________________
> > > >> > discuss mailing list     discuss at mpich.org
> > > >> > To manage subscription options or unsubscribe:
> > > >> > https://lists.mpich.org/mailman/listinfo/discuss
> > > >>
> > > >> --
> > > >> Pavan Balaji
> > > >> http://www.mcs.anl.gov/~balaji
> > > >>
> > > >> _______________________________________________
> > > >> discuss mailing list     discuss at mpich.org
> > > >> To manage subscription options or unsubscribe:
> > > >> https://lists.mpich.org/mailman/listinfo/discuss
> > > >>
> > > >>
> > > >> _______________________________________________
> > > >> discuss mailing list     discuss at mpich.org
> > > >> To manage subscription options or unsubscribe:
> > > >> https://lists.mpich.org/mailman/listinfo/discuss
> > > >
> > > > _______________________________________________
> > > > discuss mailing list     discuss at mpich.org
> > > > To manage subscription options or unsubscribe:
> > > > https://lists.mpich.org/mailman/listinfo/discuss
> > > >
> > > > _______________________________________________
> > > > discuss mailing list     discuss at mpich.org
> > > > To manage subscription options or unsubscribe:
> > > > https://lists.mpich.org/mailman/listinfo/discuss
> > >
> > > --
> > > Pavan Balaji
> > > http://www.mcs.anl.gov/~balaji
> > >
> > > _______________________________________________
> > > discuss mailing list     discuss at mpich.org
> > > To manage subscription options or unsubscribe:
> > > https://lists.mpich.org/mailman/listinfo/discuss
> > >
> > > _______________________________________________
> > > discuss mailing list     discuss at mpich.org
> > > To manage subscription options or unsubscribe:
> > > https://lists.mpich.org/mailman/listinfo/discuss
> >
> > --
> > Pavan Balaji
> > http://www.mcs.anl.gov/~balaji
> >
> > _______________________________________________
> > discuss mailing list     discuss at mpich.org
> > To manage subscription options or unsubscribe:
> > https://lists.mpich.org/mailman/listinfo/discuss
> >
> >
> >
> > <backtrace2.txt>_______________________________________________
> > discuss mailing list     discuss at mpich.org
> > To manage subscription options or unsubscribe:
> > https://lists.mpich.org/mailman/listinfo/discuss
>
> --
> Pavan Balaji
> http://www.mcs.anl.gov/~balaji
>
> _______________________________________________
> discuss mailing list     discuss at mpich.org
> To manage subscription options or unsubscribe:
> https://lists.mpich.org/mailman/listinfo/discuss
>
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