[mpich-discuss] MPI memory allocation.

[Pavan Balaji]

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.
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> --
> Pavan Balaji
> http://www.mcs.anl.gov/~balaji
> 
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--
Pavan Balaji
http://www.mcs.anl.gov/~balaji