// SPDX-License-Identifier: BSD-3-Clause
/*
 * evhold.cu - deterministic event-holder / event-wait probe for the guest
 * event-delivery class (r577). Opens a CUDA context (so the driver
 * registers its RM events), runs one small op, records and synchronizes a
 * CUDA event (which exercises the client's wait path), then holds the
 * context open for N seconds so host-side experiments (rmpost rounds with
 * the gsp_rm_ev_* knobs, ev_post kprobe) have a live event table to post
 * into.
 *
 * Usage: evhold [hold_seconds]
 * Output lines:
 *   EVHOLD ctx ok
 *   EVHOLD event sync ok
 *   EVHOLD hold done
 */
#include <cstdio>
#include <cstdlib>
#include <unistd.h>
#include <cuda_runtime.h>

static void check(const char *what, cudaError_t e)
{
    if (e != cudaSuccess) {
        printf("EVHOLD FAIL %s: %s\n", what, cudaGetErrorString(e));
        fflush(stdout);
        exit(1);
    }
}

int main(int argc, char **argv)
{
    int hold = (argc > 1) ? atoi(argv[1]) : 120;
    float *d = NULL;
    cudaEvent_t ev;

    check("freectx", cudaFree(0));
    printf("EVHOLD ctx ok\n");
    fflush(stdout);

    check("malloc", cudaMalloc(&d, 4096));
    check("memset", cudaMemset(d, 0, 4096));
    check("evcreate", cudaEventCreate(&ev));
    check("evrecord", cudaEventRecord(ev, 0));
    check("evsync", cudaEventSynchronize(ev));
    printf("EVHOLD event sync ok\n");
    fflush(stdout);

    for (int i = 0; i < hold; i++)
        sleep(1);

    cudaEventDestroy(ev);
    cudaFree(d);
    printf("EVHOLD hold done\n");
    return 0;
}