VILLASnode/clients/shmem/villas-shmem.cpp

/* Test "client" for the shared memory interface.
 *
 * Waits on the incoming queue, prints received samples and writes them
 * back to the other queue.
 *
 * Author: Georg Martin Reinke <georg.reinke@rwth-aachen.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <atomic>
#include <iostream>

#include <villas/colors.hpp>
#include <villas/log.hpp>
#include <villas/node.hpp>
#include <villas/node/config.hpp>
#include <villas/node/exceptions.hpp>
#include <villas/pool.hpp>
#include <villas/sample.hpp>
#include <villas/shmem.hpp>
#include <villas/tool.hpp>
#include <villas/utils.hpp>

namespace villas {
namespace node {
namespace tools {

class Shmem : public Tool {

public:
  Shmem(int argc, char *argv[]) : Tool(argc, argv, "shmem"), stop(false) {}

protected:
  std::atomic<bool> stop;

  void usage() {
    std::cout
        << "Usage: villas-test-shmem WNAME VECTORIZE" << std::endl
        << "  WNAME     name of the shared memory object for the output queue"
        << std::endl
        << "  RNAME     name of the shared memory object for the input queue"
        << std::endl
        << "  VECTORIZE maximum number of samples to read/write at a time"
        << std::endl;

    printCopyright();
  }

  void handler(int, siginfo_t *, void *) { stop = true; }

  int main() {
    int ret, readcnt, writecnt, avail;

    struct ShmemInterface shm;
    struct ShmemConfig conf = {.polling = 0,
                               .queuelen = DEFAULT_SHMEM_QUEUELEN,
                               .samplelen = DEFAULT_SHMEM_SAMPLELEN};

    if (argc != 4) {
      usage();
      return 1;
    }

    std::string wname = argv[1];
    std::string rname = argv[2];
    int vectorize = atoi(argv[3]);

    ret = shmem_int_open(wname.c_str(), rname.c_str(), &shm, &conf);
    if (ret < 0)
      throw RuntimeError("Failed to open shared-memory interface");

    struct Sample *insmps[vectorize], *outsmps[vectorize];

    while (!stop) {
      readcnt = shmem_int_read(&shm, insmps, vectorize);
      if (readcnt == -1) {
        logger->info("Node stopped, exiting");
        break;
      }

      avail = shmem_int_alloc(&shm, outsmps, readcnt);
      if (avail < readcnt)
        logger->warn("Pool underrun: {} / {}", avail, readcnt);

      for (int i = 0; i < avail; i++) {
        outsmps[i]->sequence = insmps[i]->sequence;
        outsmps[i]->ts = insmps[i]->ts;

        int len = MIN(insmps[i]->length, outsmps[i]->capacity);
        memcpy(outsmps[i]->data, insmps[i]->data, SAMPLE_DATA_LENGTH(len));

        outsmps[i]->length = len;
      }

      for (int i = 0; i < readcnt; i++)
        sample_decref(insmps[i]);

      writecnt = shmem_int_write(&shm, outsmps, avail);
      if (writecnt < avail)
        logger->warn("Short write");

      logger->info("Read / Write: {}/{}", readcnt, writecnt);
    }

    ret = shmem_int_close(&shm);
    if (ret)
      throw RuntimeError("Failed to close shared-memory interface");

    return 0;
  }
};

} // namespace tools
} // namespace node
} // namespace villas

int main(int argc, char *argv[]) {
  villas::node::tools::Shmem t(argc, argv);

  return t.run();
}