openmpi/opal/mca/pmix/cray/pmix_cray.c

/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2007      The Trustees of Indiana University.
 *                         All rights reserved.
 * Copyright (c) 2011      Cisco Systems, Inc.  All rights reserved.
 * Copyright (c) 2011-2013 Los Alamos National Security, LLC. All
 *                         rights reserved.
 * Copyright (c) 2013-2014 Intel, Inc.  All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

#include "opal_config.h"
#include "opal/constants.h"
#include "opal/types.h"

#include "opal_stdint.h"
#include "opal/mca/hwloc/base/base.h"
#include "opal/util/output.h"
#include "opal/util/proc.h"
#include "opal/util/output.h"
#include "opal/util/show_help.h"

#include <string.h>
#include <pmi.h>
#include <pmi2.h>

#include "opal/mca/pmix/base/base.h"
#include "pmix_cray.h"

typedef struct {
    uint32_t jid;
    uint32_t vid;
} pmix_pname_t;

static int cray_init(void);
static int cray_fini(void);
static bool cray_initialized(void);
static int cray_abort(int flag, const char msg[]);
static int cray_spawn(int count, const char * cmds[],
        int argcs[], const char ** argvs[],
        const int maxprocs[],
        opal_list_t *info_keyval_vector,
        opal_list_t *preput_keyval_vector,
        char jobId[], int jobIdSize,
        int errors[]);
static int cray_job_connect(const char jobId[]);
static int cray_job_disconnect(const char jobId[]);
static int cray_put(opal_pmix_scope_t scope, opal_value_t *kv);
static int cray_fence(opal_process_name_t *procs, size_t nprocs);
static int cray_get(const opal_identifier_t *id,
                    const char *key,
                    opal_value_t **kv);
static int cray_publish(const char service_name[],
                      opal_list_t *info,
                      const char port[]);
static int cray_lookup(const char service_name[],
                       opal_list_t *info,
                       char port[], int portLen);
static int cray_unpublish(const char service_name[],
                          opal_list_t *info);
static bool cray_get_attr(const char *attr, opal_value_t **kv);
static int kvs_get(const char key[], char value [], int maxvalue);
#if 0
static int cray_get_jobid(char jobId[], int jobIdSize);
static int cray_get_rank(int *rank);
static int cray_get_size(opal_pmix_scope_t scope, int *size);
static int cray_get_appnum(int *appnum);
static int cray_local_info(int vpid, int **ranks_ret,
                           int *procs_ret, char **error);
#endif

const opal_pmix_base_module_t opal_pmix_cray_module = {
    cray_init,
    cray_fini,
    cray_initialized,
    cray_abort,
    cray_fence,
    NULL,
    cray_put,
    cray_get,
    NULL,
    cray_publish,
    cray_lookup,
    cray_unpublish,
    cray_get_attr,
    NULL,
    cray_spawn,
    cray_job_connect,
    cray_job_disconnect,
    NULL,
    NULL
};

// usage accounting
static int pmix_init_count = 0;

// PMI constant values:
static int pmix_kvslen_max = 0;
static int pmix_keylen_max = 0;
static int pmix_vallen_max = 0;

// Job environment description
static int pmix_size = 0;
static int pmix_rank = 0;
static int pmix_lrank = 0;
static int pmix_nrank = 0;
static int pmix_nlranks = 0;
static int pmix_appnum = 0;
static int pmix_usize = 0;
static char *pmix_kvs_name = NULL;
static int *pmix_lranks = NULL;
static pmix_pname_t pmix_pname;
static uint32_t pmix_jobid = -1;


static char* pmix_packed_data = NULL;
static int pmix_packed_data_offset = 0;
static int pmix_pack_key = 0;
static bool pmix_got_modex_data = false;

static char* pmix_error(int pmix_err);
#define OPAL_PMI_ERROR(pmi_err, pmi_func)                       \
    do {                                                        \
        opal_output(0, "%s [%s:%d:%s]: %s\n",                   \
                    pmi_func, __FILE__, __LINE__, __func__,     \
                    pmix_error(pmi_err));                       \
    } while(0);

static int cray_init(void)
{
    int i, spawned, size, rank, appnum, my_node;
    int rc, ret = OPAL_ERROR;
    char *pmapping = NULL;
    char buf[PMI2_MAX_ATTRVALUE];
    int found;
    uint32_t jobfam;

    ++pmix_init_count;

    /* if we can't startup PMI, we can't be used */
    if ( PMI2_Initialized () ) {
        return OPAL_SUCCESS;
    }
    size = -1;
    rank = -1;
    appnum = -1;
    if (PMI_SUCCESS != (rc = PMI2_Init(&spawned, &size, &rank, &appnum))) {
        opal_show_help("help-pmix-base.txt", "pmix2-init-failed", true, rc);
        return OPAL_ERROR;
    }
    if( size < 0 || rank < 0 ){
        opal_show_help("help-pmix-base.txt", "pmix2-init-returned-bad-values", true);
        goto err_exit;
    }

    pmix_size = size;
    pmix_rank = rank;
    pmix_appnum = appnum;

    pmix_vallen_max = PMI2_MAX_VALLEN;
    pmix_kvslen_max = PMI2_MAX_VALLEN; // FIX ME: What to put here for versatility?
    pmix_keylen_max = PMI2_MAX_KEYLEN;

    rc = PMI2_Info_GetJobAttr("universeSize", buf, 16, &found);
    if( PMI_SUCCESS != rc ) {
        OPAL_PMI_ERROR(rc, "PMI_Get_universe_size");
        goto err_exit;
    }
    pmix_usize = atoi(buf);

    pmix_kvs_name = (char*)malloc(pmix_kvslen_max);
    if( pmix_kvs_name == NULL ){
         PMI2_Finalize();
         ret = OPAL_ERR_OUT_OF_RESOURCE;
         goto err_exit;
    }
    rc = PMI2_Job_GetId(pmix_kvs_name, pmix_kvslen_max);
    if( PMI_SUCCESS != rc ) {
        OPAL_PMI_ERROR(rc, "PMI2_Job_GetId");
        goto err_exit;
    }

    rc = sscanf(pmix_kvs_name,"kvs_%u",&jobfam);
    if (rc != 1) {
        OPAL_PMI_ERROR(rc, "PMI2_Job_GetId");
        rc = OPAL_ERROR;
        goto err_exit;
    }

    pmix_jobid = jobfam << 16;

    /* store our name in the opal_proc_t so that
     * debug messages will make sense - an upper
     * layer will eventually overwrite it, but that
     * won't do any harm */
    pmix_pname.jid = pmix_jobid;
    pmix_pname.vid = pmix_rank;
    opal_proc_set_name((opal_process_name_t*)&pmix_pname);
    opal_output_verbose(10, opal_pmix_base_framework.framework_output,
                        "%s pmix:cray: assigned tmp name %d %d pmix_kvs_name %s",
                        OPAL_NAME_PRINT(*(opal_process_name_t*)&pmix_pname),pmix_pname.jid,pmix_pname.vid,pmix_kvs_name);

    pmapping = (char*)malloc(PMI2_MAX_VALLEN);
    if( pmapping == NULL ){
        rc = OPAL_ERR_OUT_OF_RESOURCE;
        OPAL_ERROR_LOG(rc);
        return rc;
    }

    rc = PMI2_Info_GetJobAttr("PMI_process_mapping", pmapping, PMI2_MAX_VALLEN, &found);
    if( !found || PMI_SUCCESS != rc ) {
        OPAL_PMI_ERROR(rc,"PMI2_Info_GetJobAttr");
        return OPAL_ERROR;
    }

    pmix_lranks = pmix_cray_parse_pmap(pmapping, pmix_rank, &my_node, &pmix_nlranks);
    if (NULL == pmix_lranks) {
        rc = OPAL_ERR_OUT_OF_RESOURCE;
        OPAL_ERROR_LOG(rc);
        return rc;
    }

    free(pmapping);

    /* find ourselves */
    for (i=0; i < pmix_nlranks; i++) {
        if (pmix_rank == pmix_lranks[i]) {
            pmix_lrank = i;
            pmix_nrank = i;
            break;
        }
    }

    return OPAL_SUCCESS;
err_exit:
    PMI2_Finalize();
    return ret;
}

static int cray_fini(void) {

    if (0 == pmix_init_count) {
        return OPAL_SUCCESS;
    }

    if (0 == --pmix_init_count) {
        PMI2_Finalize();
    }

    if (NULL != pmix_kvs_name) {
        free(pmix_kvs_name);
        pmix_kvs_name = NULL;
    }

    if (NULL != pmix_lranks) {
        free(pmix_lranks);
        pmix_lranks = NULL;
    }

    return OPAL_SUCCESS;
}

static bool cray_initialized(void)
{
    if (0 < pmix_init_count) {
        return true;
    }
    return false;
}

static int cray_abort(int status, const char *msg)
{
    return PMI2_Abort(status, msg);
}

static int cray_spawn(int count, const char * cmds[],
        int argcs[], const char ** argvs[],
        const int maxprocs[],
        opal_list_t *info_keyval_vector,
        opal_list_t *preput_keyval_vector,
        char jobId[], int jobIdSize,
        int errors[])
{
    return OPAL_ERR_NOT_IMPLEMENTED;
}

#if 0
static int cray_get_jobid(char jobId[], int jobIdSize)
{
    return PMI2_Job_GetId(jobId,jobIdSize);
}

static int cray_get_rank(int *rank)
{
    *rank = pmix_rank;
    return OPAL_SUCCESS;
}

static int cray_get_size(opal_pmix_scope_t scope, int *size)
{
    *size = pmix_size;
    return OPAL_SUCCESS;
}

static int cray_get_appnum(int *appnum)
{
    *appnum = pmix_appnum;
    return OPAL_SUCCESS;
}
#endif

static int cray_job_connect(const char jobId[])
{
    return OPAL_ERR_NOT_IMPLEMENTED;
}

static int cray_job_disconnect(const char jobId[])
{
    return OPAL_ERR_NOT_IMPLEMENTED;
}

static int kvs_put(const char key[], const char value[])
{

    int rc;

    opal_output_verbose(10, opal_pmix_base_framework.framework_output,
                        "%s pmix:cray kvs_put key %s  value %s",
                        OPAL_NAME_PRINT(OPAL_PROC_MY_NAME), key, value);

    rc =  PMI2_KVS_Put(key, value);
    if( PMI_SUCCESS != rc ){
        OPAL_PMI_ERROR(rc, "PMI2_KVS_Put");
        return OPAL_ERROR;
    }
    return OPAL_SUCCESS;
}

static int cray_put(opal_pmix_scope_t scope,
                  opal_value_t *kv)
{
    int rc;
    char* buffer_to_put;
    int rem_offset = 0;
    int data_to_put = 0;

    opal_output_verbose(10, opal_pmix_base_framework.framework_output,
                        "%s pmix:cray cray_put my name is %ld\n",
                         OPAL_NAME_PRINT(OPAL_PROC_MY_NAME), opal_proc_local_get()->proc_name);

    if (OPAL_SUCCESS != (rc = opal_pmix_base_store_encoded (kv->key, (void*)&kv->data, kv->type, 
                                                            &pmix_packed_data, &pmix_packed_data_offset))) {
        OPAL_ERROR_LOG(rc);
        return rc;
    }

    if (pmix_packed_data_offset == 0) {
        /* nothing to write */
        return OPAL_SUCCESS;
    }

    if (pmix_packed_data_offset < pmix_vallen_max) {
        /* this meta-key is still being filled,
         * nothing to put yet
         */
        return OPAL_SUCCESS;
    }

    /* encode only full filled meta keys */
    rem_offset = pmix_packed_data_offset % pmix_vallen_max;
    data_to_put = pmix_packed_data_offset - rem_offset;
    buffer_to_put = (char*)malloc(data_to_put);
    memcpy(buffer_to_put, pmix_packed_data, data_to_put);

    opal_pmix_base_commit_packed (buffer_to_put, data_to_put, pmix_vallen_max, &pmix_pack_key, kvs_put);

    free(buffer_to_put);
    pmix_packed_data_offset = rem_offset;
    if (0 == pmix_packed_data_offset) {
        free(pmix_packed_data);
        pmix_packed_data = NULL;
    } else {
        memmove (pmix_packed_data, pmix_packed_data + data_to_put, pmix_packed_data_offset);
        pmix_packed_data = realloc (pmix_packed_data, pmix_packed_data_offset);
    }

    return rc;
}

static int cray_fence(opal_process_name_t *procs, size_t nprocs)
{
    int rc;
    int32_t i;
    opal_value_t *kp, kvn;
    opal_hwloc_locality_t locality;

    opal_output_verbose(10, opal_pmix_base_framework.framework_output,
                        "%s pmix:cray called fence",
                        OPAL_NAME_PRINT(OPAL_PROC_MY_NAME));

    /* check if there is partially filled meta key and put them */
    if (0 != pmix_packed_data_offset && NULL != pmix_packed_data) {
        opal_pmix_base_commit_packed(pmix_packed_data, pmix_packed_data_offset, pmix_vallen_max, &pmix_pack_key, kvs_put);
        pmix_packed_data_offset = 0;
        free(pmix_packed_data);
        pmix_packed_data = NULL;
    }

    if (PMI_SUCCESS != (rc = PMI2_KVS_Fence())) {
        OPAL_PMI_ERROR(rc, "PMI2_KVS_Fence");
        return OPAL_ERROR;
    }

    opal_output_verbose(10, opal_pmix_base_framework.framework_output,
                        "%s pmix:cray kvs_fence complete",
                        OPAL_NAME_PRINT(OPAL_PROC_MY_NAME));

    /* get the modex data from each local process and set the
     * localities to avoid having the MPI layer fetch data
     * for every process in the job */
    if (!pmix_got_modex_data) {
        pmix_got_modex_data = true;
        /* we only need to set locality for each local rank as "not found"
         * equates to "non-local" */
        for (i=0; i < pmix_nlranks; i++) {
            pmix_pname.vid = pmix_lranks[i];
            rc = opal_pmix_base_cache_keys_locally((opal_identifier_t*)&pmix_pname, OPAL_DSTORE_CPUSET,
                                                   &kp, pmix_kvs_name, pmix_vallen_max, kvs_get);
            if (OPAL_SUCCESS != rc) {
                OPAL_ERROR_LOG(rc);
                return rc;
            }
#if OPAL_HAVE_HWLOC
            if (NULL == kp || NULL == kp->data.string) {
                /* if we share a node, but we don't know anything more, then
                 * mark us as on the node as this is all we know
                 */
                locality = OPAL_PROC_ON_CLUSTER | OPAL_PROC_ON_CU | OPAL_PROC_ON_NODE;
            } else {
                /* determine relative location on our node */
                locality = opal_hwloc_base_get_relative_locality(opal_hwloc_topology,
                                                                 opal_process_info.cpuset,
                                                                 kp->data.string);
            }
            if (NULL != kp) {
                OBJ_RELEASE(kp);
            }
#else
            /* all we know is we share a node */
            locality = OPAL_PROC_ON_CLUSTER | OPAL_PROC_ON_CU | OPAL_PROC_ON_NODE;
#endif
            OPAL_OUTPUT_VERBOSE((1, opal_pmix_base_framework.framework_output,
                                 "%s pmix:s2 proc %s locality %s",
                                 OPAL_NAME_PRINT(OPAL_PROC_MY_NAME),
                                 OPAL_NAME_PRINT(*(opal_identifier_t*)&pmix_pname),
                                 opal_hwloc_base_print_locality(locality)));

            OBJ_CONSTRUCT(&kvn, opal_value_t);
            kvn.key = strdup(OPAL_DSTORE_LOCALITY);
            kvn.type = OPAL_UINT16;
            kvn.data.uint16 = locality;
            (void)opal_dstore.store(opal_dstore_internal, (opal_identifier_t*)&pmix_pname, &kvn);
            OBJ_DESTRUCT(&kvn);
        }
    }

    return OPAL_SUCCESS;
}

#if 0
static int cray_fence(opal_process_name_t *procs, size_t nprocs)
{
    int rc;

    /* check if there is partially filled meta key and put them */
    if (0 != pmix_packed_data_offset && NULL != pmix_packed_data) {
        opal_pmix_base_commit_packed(pmix_packed_data, pmix_packed_data_offset, pmix_vallen_max, &pmix_pack_key, kvs_put);
        pmix_packed_data_offset = 0;
        free(pmix_packed_data);
        pmix_packed_data = NULL;
    }

    if (PMI_SUCCESS != (rc = PMI2_KVS_Fence())) {
        OPAL_PMI_ERROR(rc, "PMI2_KVS_Fence");
        return OPAL_ERROR;
    }

    return OPAL_SUCCESS;
}
#endif

static int kvs_get(const char key[], char value [], int maxvalue)
{
    int rc;
    int len;

    rc = PMI2_KVS_Get(pmix_kvs_name, PMI2_ID_NULL, key, value, maxvalue, &len);
    if( PMI_SUCCESS != rc ){
        OPAL_PMI_ERROR(rc, "PMI2_KVS_Get");
        return OPAL_ERROR;
    }
    return OPAL_SUCCESS;
}

static int cray_get(const opal_identifier_t *id, const char *key, opal_value_t **kv)
{
    int rc;
    rc = opal_pmix_base_cache_keys_locally(id, key, kv, pmix_kvs_name, pmix_vallen_max, kvs_get);
    return rc;
}

static int cray_publish(const char service_name[],
                        opal_list_t *info,
                        const char port[])
{
    int rc;

    if (PMI_SUCCESS != (rc = PMI2_Nameserv_publish(service_name, NULL, port))) {
        OPAL_PMI_ERROR(rc, "PMI2_Nameserv_publish");
        return OPAL_ERROR;
    }
    return OPAL_SUCCESS;
}

static int cray_lookup(const char service_name[],
                       opal_list_t *info,
                       char port[], int portLen)
{
    int rc;

    if (PMI_SUCCESS != (rc = PMI2_Nameserv_lookup(service_name, NULL, port, portLen))) {
        OPAL_PMI_ERROR(rc, "PMI2_Nameserv_lookup");
        return OPAL_ERROR;
    }

    return OPAL_SUCCESS;
}

static int cray_unpublish(const char service_name[],
                          opal_list_t *info)
{
    int rc;

    if (PMI_SUCCESS != (rc = PMI2_Nameserv_unpublish(service_name, NULL))) {
        OPAL_PMI_ERROR(rc, "PMI2_Nameserv_unpublish");
        return OPAL_ERROR;
    }
    return OPAL_SUCCESS;;
}

static bool cray_get_attr(const char *attr, opal_value_t **kv)
{
    int rc, i;
    opal_value_t *kp;

    if (0 == strcmp(PMIX_JOBID, attr)) {
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = pmix_jobid;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_RANK, attr)) {
        rc = PMI_Get_rank(&i);
        if( PMI_SUCCESS != rc ) {
            OPAL_PMI_ERROR(rc, "PMI_Get_rank");
            return false;
        }
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = i;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_UNIV_SIZE, attr)) {
        rc = PMI_Get_universe_size(&i);
        if( PMI_SUCCESS != rc ) {
            OPAL_PMI_ERROR(rc, "PMI_Get_universe_size");
            return false;
        }
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = i;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_JOB_SIZE, attr)) {
        rc = PMI_Get_size(&i);
        if( PMI_SUCCESS != rc ) {
            OPAL_PMI_ERROR(rc, "PMI_Get_size");
            return false;
        }
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = i;
        *kv = kp;
        return true;
    }


    if (0 == strcmp(PMIX_APPNUM, attr)) {
        rc = PMI_Get_appnum(&i);
        if( PMI_SUCCESS != rc ) {
            OPAL_PMI_ERROR(rc, "PMI_Get_appnum");
            return false;
        }
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = i;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_LOCAL_RANK, attr)) {
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = pmix_lrank;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_NODE_RANK, attr)) {
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = pmix_nrank;
        *kv = kp;
        return true;
    }

    if (0 == strcmp(PMIX_LOCAL_SIZE, attr)) {
        kp = OBJ_NEW(opal_value_t);
        kp->key = strdup(attr);
        kp->type = OPAL_UINT32;
        kp->data.uint32 = pmix_nlranks;
        *kv = kp;
        return true;
    }

    return OPAL_ERR_NOT_IMPLEMENTED;
}


#if 0
static int cray_local_info(int vpid, int **ranks_ret,
                           int *procs_ret, char **error)
{
    int *ranks;
    int procs = -1;
    int rc;

    char *pmapping = (char*)malloc(PMI2_MAX_VALLEN);
    if( pmapping == NULL ){
        *error = "mca_common_pmix_local_info: could not get memory for PMIv2 process mapping";
        return OPAL_ERR_OUT_OF_RESOURCE;
    }
    int found;
    int my_node;

    rc = PMI2_Info_GetJobAttr("PMI_process_mapping", pmapping, PMI2_MAX_VALLEN, &found);
    if( !found || PMI_SUCCESS != rc ) {
        /* can't check PMI_SUCCESS as some folks (i.e., Cray) don't define it */
        OPAL_PMI_ERROR(rc,"PMI2_Info_GetJobAttr");
        *error = "mca_common_pmix_local_info: could not get PMI_process_mapping";
        return OPAL_ERROR;
    }

    ranks = pmix_cray_parse_pmap(pmapping, vpid, &my_node, &procs);
    if (NULL == ranks) {
        *error = "mca_common_pmix_local_info: could not get memory for PMIv2 local ranks";
        return OPAL_ERR_OUT_OF_RESOURCE;
    }

    free(pmapping);
    *ranks_ret = ranks;
    *procs_ret = procs;
    return OPAL_SUCCESS;
}
#endif

static char* pmix_error(int pmix_err)
{
    char * err_msg;

    switch(pmix_err) {
        case PMI_FAIL: err_msg = "Operation failed"; break;
        case PMI_ERR_INIT: err_msg = "PMI is not initialized"; break;
        case PMI_ERR_NOMEM: err_msg = "Input buffer not large enough"; break;
        case PMI_ERR_INVALID_ARG: err_msg = "Invalid argument"; break;
        case PMI_ERR_INVALID_KEY: err_msg = "Invalid key argument"; break;
        case PMI_ERR_INVALID_KEY_LENGTH: err_msg = "Invalid key length argument"; break;
        case PMI_ERR_INVALID_VAL: err_msg = "Invalid value argument"; break;
        case PMI_ERR_INVALID_VAL_LENGTH: err_msg = "Invalid value length argument"; break;
        case PMI_ERR_INVALID_LENGTH: err_msg = "Invalid length argument"; break;
        case PMI_ERR_INVALID_NUM_ARGS: err_msg = "Invalid number of arguments"; break;
        case PMI_ERR_INVALID_ARGS: err_msg = "Invalid args argument"; break;
        case PMI_ERR_INVALID_NUM_PARSED: err_msg = "Invalid num_parsed length argument"; break;
        case PMI_ERR_INVALID_KEYVALP: err_msg = "Invalid keyvalp argument"; break;
        case PMI_ERR_INVALID_SIZE: err_msg = "Invalid size argument"; break;
#if defined(PMI_ERR_INVALID_KVS)
	/* pmi.h calls this a valid return code but mpich doesn't define it (slurm does). */
        case PMI_ERR_INVALID_KVS: err_msg = "Invalid kvs argument"; break;
#endif
        case PMI_SUCCESS: err_msg = "Success"; break;
        default: err_msg = "Unkown error";
    }
    return err_msg;
}