[mpich-devel] ROMIO collective i/o memory use

[Rob Latham]

On Mon, Apr 29, 2013 at 10:28:01AM -0500, Bob Cernohous wrote:
> A customer (Argonne ;) is complaining about O(p) allocations in collective 
> i/o.  A collective read is failing at larger scale. 
> 
> Any thoughts or comments or advice?   There appears to be lots of O(p) in 
> ROMIO collective I/O.  Plus a lot of (possibly large) aggregated data 
> buffers.  A quick search shows

The O(p) allocations are a concern, sure.  For two-phase, though, the
real problem lies in ADIOI_R_Exchange_data_alltoallv and
ADIOI_W_Exchange_data_alltoallv .  The O(p) allocations are the least
of our worries! 

around line 1063 of ad_bg_rdcoll.c 

all_recv_buf = (char *) ADIOI_Malloc( rtail );

all_send_buf = (char *) ADIOI_Malloc( stail );

(rtail and stail are the sum of the receive and send arrays)

==rob

> The common ROMIO read collective code:
> 
> Find all "ADIOI_Malloc", Match case, Regular expression (UNIX)
> 
> File Z:\bgq\comm\lib\dev\mpich2\src\mpi\romio\adio\common\ad_read_coll.c
> 
>   124 38:       st_offsets = (ADIO_Offset *) 
> ADIOI_Malloc(nprocs*sizeof(ADIO_Offset));
> 
>   125 39:       end_offsets = (ADIO_Offset *) 
> ADIOI_Malloc(nprocs*sizeof(ADIO_Offset));
> 
>   317 44:       *offset_list_ptr = (ADIO_Offset *) 
> ADIOI_Malloc(2*sizeof(ADIO_Offset));
> 
>   318 41:       *len_list_ptr = (ADIO_Offset *) 
> ADIOI_Malloc(2*sizeof(ADIO_Offset));
> 
>   334 44:       *offset_list_ptr = (ADIO_Offset *) 
> ADIOI_Malloc(2*sizeof(ADIO_Offset));
> 
>   335 41:       *len_list_ptr = (ADIO_Offset *) 
> ADIOI_Malloc(2*sizeof(ADIO_Offset));
> 
>   436 18: ADIOI_Malloc((contig_access_count+1)*sizeof(ADIO_Offset)); 
> 
>   437 41:       *len_list_ptr = (ADIO_Offset *) 
> ADIOI_Malloc((contig_access_count+1)*sizeof(ADIO_Offset));
> 
>   573 37:    if (ntimes) read_buf = (char *) ADIOI_Malloc(coll_bufsize);
> 
>   578 21:    count = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   587 25:    send_size = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   590 25:    recv_size = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   598 25:    start_pos = (int *) ADIOI_Malloc(nprocs*sizeof(int));
> 
>   739 32:           tmp_buf = (char *) ADIOI_Malloc(for_next_iter);
> 
>   744 33:           read_buf = (char *) 
> ADIOI_Malloc(for_next_iter+coll_bufsize);
> 
>   805 9: ADIOI_Malloc((nprocs_send+nprocs_recv+1)*sizeof(MPI_Request));
> 
>   827 30:       recv_buf = (char **) ADIOI_Malloc(nprocs * sizeof(char*));
> 
>   830 44:                                  (char *) 
> ADIOI_Malloc(recv_size[i]);
> 
>   870 31:    statuses = (MPI_Status *) 
> ADIOI_Malloc((nprocs_send+nprocs_recv+1) * \
> 
>   988 35:    curr_from_proc = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
>   989 35:    done_from_proc = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
>   990 35:    recv_buf_idx   = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
> Total found: 22
> 
> 
> Our BG version of read collective:
> 
> File Z:\bgq\comm\lib\dev\mpich2\src\mpi\romio\adio\ad_bg\ad_bg_rdcoll.c
> 
>   179 40:       st_offsets   = (ADIO_Offset *) 
> ADIOI_Malloc(nprocs*sizeof(ADIO_Offset));
> 
>   180 40:       end_offsets  = (ADIO_Offset *) 
> ADIOI_Malloc(nprocs*sizeof(ADIO_Offset));
> 
>   183 43:           bg_offsets0 = (ADIO_Offset *) 
> ADIOI_Malloc(2*nprocs*sizeof(ADIO_Offset));
> 
>   184 43:           bg_offsets  = (ADIO_Offset *) 
> ADIOI_Malloc(2*nprocs*sizeof(ADIO_Offset));
> 
>   475 37:    if (ntimes) read_buf = (char *) ADIOI_Malloc(coll_bufsize);
> 
>   480 21:    count = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   489 25:    send_size = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   492 25:    recv_size = (int *) ADIOI_Malloc(nprocs * sizeof(int));
> 
>   500 25:    start_pos = (int *) ADIOI_Malloc(nprocs*sizeof(int));
> 
>   676 32:           tmp_buf = (char *) ADIOI_Malloc(for_next_iter);
> 
>   681 33:           read_buf = (char *) 
> ADIOI_Malloc(for_next_iter+coll_bufsize);
> 
>   761 9: ADIOI_Malloc((nprocs_send+nprocs_recv+1)*sizeof(MPI_Request));
> 
>   783 30:       recv_buf = (char **) ADIOI_Malloc(nprocs * sizeof(char*));
> 
>   786 44:                                  (char *) 
> ADIOI_Malloc(recv_size[i]);
> 
>   826 31:    statuses = (MPI_Status *) 
> ADIOI_Malloc((nprocs_send+nprocs_recv+1) * \
> 
>   944 35:    curr_from_proc = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
>   945 35:    done_from_proc = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
>   946 35:    recv_buf_idx   = (unsigned *) ADIOI_Malloc(nprocs * 
> sizeof(unsigned));
> 
>   1058 23:    rdispls = (int *) ADIOI_Malloc( nprocs * sizeof(int) );
> 
>   1063 29:    all_recv_buf = (char *) ADIOI_Malloc( rtail );
> 
>   1064 26:    recv_buf = (char **) ADIOI_Malloc(nprocs * sizeof(char *));
> 
>   1068 23:    sdispls = (int *) ADIOI_Malloc( nprocs * sizeof(int) );
> 
>   1073 29:    all_send_buf = (char *) ADIOI_Malloc( stail );
> 
> Total found: 23
> 
> 
> Bob Cernohous:  (T/L 553) 507-253-6093
> 
> BobC at us.ibm.com
> IBM Rochester, Building 030-2(C335), Department 61L
> 3605 Hwy 52 North, Rochester,  MN 55901-7829
> 
> > Chaos reigns within.
> > Reflect, repent, and reboot.
> > Order shall return.

-- 
Rob Latham
Mathematics and Computer Science Division
Argonne National Lab, IL USA