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Subject: Re: [OMPI users] Problem with OpenMPI (MX btl and mtl) and threads
From: Scott Atchley (atchley_at_[hidden])
Date: 2009-06-12 10:49:26


Francois,

How many cores do your machines have?

The file specifies THREADS_DEFAULT 16. Does this spawn 16 threads per
MPI rank?

I see crashes when I run this with MX (BTL with mx,sm,self and MTL).
If I change THREADS_DEFAULT to 4, I see crashes with TCP (BTL with
tcp,sm,self) as well.

With THREADS_DEFAULT at 16, TCP seems to hang. I only have 2 cores,
which mmay be why. :-)

Scott

On Jun 12, 2009, at 3:09 AM, François Trahay wrote:

> Here's the program.
> It should print something like that:
>
> [1 communicating threads]
> [0] 1 2.484936 0.402 0.384
> [0] 2 2.478036 0.807 0.770
> [0] 4 2.501503 1.599 1.525
> [0] 8 2.497516 3.203 3.055
> thread #1
> [2 communicating threads]
> [0] 1 3.970628 0.252 0.240
> [1] 1 3.929280 0.254 0.243
> [1] 2 4.087206 0.489 0.467
> [0] 2 5.181758 0.386 0.368
> [1] 4 3.715222 1.077 1.027
> [0] 4 4.358013 0.918 0.875
> [1] 8 4.166852 1.920 1.831
> [0] 8 3.628287 2.205 2.103
> thread #2
> [3 communicating threads]
> [0] 1 5.922241 0.169 0.161
> [2] 1 6.896299 0.145 0.138
> [1] 1 8.973834 0.111 0.106
> ...
>
>
> Francois
>
> George Bosilca wrote:
>> I will take a look at the BTL problem. Can you provide a copy of
>> the benchmarks please.
>>
>> Thanks,
>> george.
>>
>> On Jun 11, 2009, at 16:05 , François Trahay wrote:
>>
>>> concurrent_ping
>>
>>
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>
> /*
> * NewMadeleine
> * Copyright (C) 2006 (see AUTHORS file)
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License as published by
> * the Free Software Foundation; either version 2 of the License, or
> (at
> * your option) any later version.
> *
> * This program is distributed in the hope that it will be useful, but
> * WITHOUT ANY WARRANTY; without even the implied warranty of
> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> * General Public License for more details.
> */
> #include <stdlib.h>
> #include <stdio.h>
> #include <stdint.h>
> #include <string.h>
> #include <unistd.h>
> #include "mpi.h"
>
> #include <semaphore.h>
> #include <sched.h>
>
> /* This program performs several ping pong in parallel.
> * This evaluates the efficienty to access nmad from 1, 2, 3, ...n
> threads simultanously
> */
>
> #define LEN_DEFAULT 4
> #define WARMUPS_DEFAULT 1000
> #define LOOPS_DEFAULT 10000
> #define THREADS_DEFAULT 16
> #define DATA_CONTROL_ACTIVATED 0
>
> static int comm_rank = -1;
> static int comm_size = -1;
> static char host_name[1024] = "";
>
> static int max_len = 16;
> static int loops;
> static int threads;
> static int warmups;
>
> static sem_t ready_sem;
>
> static int go;
>
> static __inline__
> uint32_t _next(uint32_t len, uint32_t multiplier, uint32_t increment)
> {
> if (!len)
> return 1+increment;
> else
> return len*multiplier+increment;
> }
>
> void usage_ping() {
> fprintf(stderr, "-L len - packet length [%d]\n", LEN_DEFAULT);
> fprintf(stderr, "-N iterations - iterations [%d]\n", LOOPS_DEFAULT);
> fprintf(stderr, "-T thread - number of communicating threads [%d]
> \n", THREADS_DEFAULT);
> fprintf(stderr, "-W warmup - number of warmup iterations [%d]\n",
> WARMUPS_DEFAULT);
> }
>
> static void fill_buffer(char *buffer, int len) {
> unsigned int i = 0;
>
> for (i = 0; i < len; i++) {
> buffer[i] = 'a'+(i%26);
> }
> }
>
> static void clear_buffer(char *buffer, int len) {
> memset(buffer, 0, len);
> }
>
> #if DATA_CONTROL_ACTIVATED
> static void control_buffer(char *msg, char *buffer, int len) {
> tbx_bool_t ok = tbx_true;
> unsigned char expected_char;
> unsigned int i = 0;
>
> for(i = 0; i < len; i++){
> expected_char = 'a'+(i%26);
>
> if(buffer[i] != expected_char){
> printf("Bad data at byte %d: expected %c, received %c\n",
> i, expected_char, buffer[i]);
> ok = tbx_false;
> }
> }
>
>
> if (!ok) {
> printf("Controling %s - ", msg);
> printf("%d bytes reception failed\n", len);
>
> TBX_FAILURE("data corruption");
> } else {
> printf("ok\n");
> }
> }
> #endif
>
>
> void
> server(void* arg) {
> int my_pos = (uint8_t)arg;
> char *buf = NULL;
> uint8_t tag = (uint8_t)arg;
> int i, k;
> int len;
>
> buf = malloc(max_len);
> clear_buffer(buf, max_len);
> for(i = my_pos; i <= threads; i++) {
> /* Be sure all the communicating threads have been created before
> we start */
> while(go < i )
> sched_yield();
>
> for(len=1; len < max_len; len*=2){
> for(k = 0; k < loops + warmups; k++) {
>
> MPI_Request request;
>
> MPI_Recv(buf, len, MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD, MPI_STATUS_IGNORE);
>
> #if DATA_CONTROL_ACTIVATED
> control_buffer("received", buf, len);
> #endif
> MPI_Send(buf, len , MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD);
>
> }
> }
>
> sem_post(&ready_sem);
> }
> }
>
> int
> client(void *arg) {
> int my_pos = (uint8_t)arg;
> uint8_t tag = (uint8_t)my_pos;
> char *buf = NULL;
> double t1, t2;
> double sum, lat, bw_million_byte, bw_mbyte;
> int i, k;
> int len;
>
> fprintf(stderr, "thread #%d\n", my_pos);
> buf = malloc(max_len);
> clear_buffer(buf, max_len);
>
> fill_buffer(buf, len);
> for(i = my_pos; i <= threads; i++) {
> /* Be sure all the communicating threads have been created before
> we start */
> while(go < i )
> sched_yield();
>
> for(len=1; len < max_len; len*=2){
> for(k = 0; k < warmups; k++) {
> MPI_Request request;
> #if DATA_CONTROL_ACTIVATED
> control_buffer("sending", buf, len);
> #endif
> MPI_Send(buf, len, MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD);
>
> MPI_Recv(buf, len, MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD, MPI_STATUS_IGNORE);
> #if DATA_CONTROL_ACTIVATED
> control_buffer("received", buf, len);
> #endif
> }
>
> t1= MPI_Wtime();
>
> for(k = 0; k < loops; k++) {
> MPI_Request request;
> #if DATA_CONTROL_ACTIVATED
> control_buffer("sending", buf, len);
> #endif
> MPI_Send(buf, len, MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD);
> MPI_Recv(buf, len, MPI_CHAR, (comm_rank+1)%2, tag,
> MPI_COMM_WORLD, MPI_STATUS_IGNORE);
> #if DATA_CONTROL_ACTIVATED
> control_buffer("received", buf, len);
> #endif
> }
>
> t2 = MPI_Wtime();
>
> sum = (t2 - t1)*1e6;
>
> lat = sum / (2 * loops);
> bw_million_byte = len * (loops / (sum / 2));
> bw_mbyte = bw_million_byte / 1.048576;
>
> printf("[%d]\t%d\t%lf\t%8.3f\t%8.3f\n", my_pos, len, lat,
> bw_million_byte, bw_mbyte);
> fflush(stdout);
> }
>
> sem_post(&ready_sem);
> }
> }
> int
> main(int argc,
> char **argv) {
> int i, j;
> pthread_t * pid;
> static sem_t bourrin_ready;
> pthread_attr_t attr;
>
> //len = LEN_DEFAULT;
> loops = LOOPS_DEFAULT;
> threads = THREADS_DEFAULT;
> warmups = WARMUPS_DEFAULT;
>
> int provided;
> int needed = MPI_THREAD_MULTIPLE;
> MPI_Init_thread(&argc, &argv, needed, &provided);
> if(provided < needed){
> fprintf(stderr, "needed: %d, provided: %d\n", needed, provided);
> exit(0);
> }
> MPI_Comm_size(MPI_COMM_WORLD, &comm_size);
> MPI_Comm_rank(MPI_COMM_WORLD, &comm_rank);
>
>
> if (argc > 1 && !strcmp(argv[1], "--help")) {
> usage_ping();
> exit(0);
> }
>
> for(i=1 ; i<argc ; i+=2) {
> if (!strcmp(argv[i], "-N")) {
> loops = atoi(argv[i+1]);
> }
> else if (!strcmp(argv[i], "-L")) {
> //len = atoi(argv[i+1]);
> }
> else if (!strcmp(argv[i], "-T")) {
> threads = atoi(argv[i+1]);
> }
> else if (!strcmp(argv[i], "-W")) {
> warmups = atoi(argv[i+1]);
> }
> else {
> fprintf(stderr, "Illegal argument %s\n", argv[i]);
> usage_ping();
> exit(0);
> }
> }
>
> pthread_attr_init(&attr);
> pid = malloc(sizeof(pthread_t) * threads);
> sem_init(&ready_sem, 0, 0);
>
> go = 0;
> for (i = 0 ; i< threads ; i++) {
> printf("[%d communicating threads]\n", i+1);
> if (comm_rank == 0) {
> pthread_create(&pid[i], &attr, (void*)server, (uint8_t)i);
> } else {
> pthread_create(&pid[i], &attr, (void*)client, (uint8_t)i);
> }
>
> for( j = 0; j <= i; j++){
> sem_wait(&ready_sem);
> go=j;
> }
> go++;
> }
>
> for(i=0;i<threads;i++)
> pthread_join(pid[i],NULL);
>
> MPI_Finalize();
> exit(0);
> }
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users