This document is relevant for: Inf2, Trn1, Trn2, Trn3

Async API Usage Examples#

Schedule#

NRT_STATUS exec_ret;

NRT_STATUS ret = nrta_execute_schedule(model, inputs, outputs, 0, &exec_ret, &seq);
if (ret != NRT_SUCCESS) {
    if (ret == NRT_QUEUE_FULL) {
        // or handle retries if desired
        break;
    }
    // handle other errors
    ...
} else {
    req_seqs[req] = seq;
}

Wait for Completion via polling#

Here’s an example for polling for completion:

nrta_seq_t last_req_seq;
nrta_seq_t completed_seq = {};
while (true) {
    nrta_get_sequence(lnc, NRTA_XU_COMPUTE, &completed_seq);
    if (completed_seq >= last_req_seq) {
        break;
    }
    usleep(1);
}

In a similar vein, we can also poll with nrta_is_completed(last_req_seq, &is_completed)

Error Handling#

We need to maintain an array/vector to track the execution return statuses.

static const int NUM_EXECS = 8;
int lnc = 0;
NRT_STATUS exec_rets[NUM_EXECS];

// submit execution requests
nrta_seq_t req_seqs[NUM_EXECS];
for (int req = 0; req < NUM_EXECS; req++) {
    nrta_seq_t seq = {};
    NRT_STATUS ret = nrta_execute_schedule(model, inputs, outputs, 0, &exec_rets[req], &seq);
    if (ret != NRT_SUCCESS) {
        if (ret == NRT_QUEUE_FULL) {
            // or handle retries if desired
            break;
        }
        // handle other errors
        ...
    } else {
        req_seqs[req] = seq;
    }
}

// check for execution errors
int error_count = 0;
for (int req = 0; req < NUM_EXECS; req++) {
    if (exec_rets[req] != NRT_SUCCESS) {
        fprintf(stderr, "Request [%x] completed with error %lu\n", req_seqs[req], exec_rets[req]);
        error_count++;
    }
}
if (error_count > 0) {
    ...
}

Finding Number of Pending Executions#

While this is susceptible to some races, here’s an example of how to estimate the outstanding requests:

nrta_seq_t last_completed = {};
const int compute_queue = 0; // Compute XU only has 1 queue
nrta_get_sequence(lnc, NRTA_XU_COMPUTE, compute_queue, &last_completed);

// sanity check: the two sequence ids should be from the same XU
assert(NRTA_SEQ_GET_XU_ID(last_submitted) == NRTA_SEQ_GET_XU_ID(last_completed));
// the sequence id is a monotone and sequential value for each XU
return last_submitted - last_completed;