Method setReaderAndWriterThreads

cachelib/allocator/nvmcache/NavyConfig.cpp:237–281

// job scheduler settings

void NavyConfig::setReaderAndWriterThreads(unsigned int readerThreads,
                                           unsigned int writerThreads,
                                           unsigned int maxNumReads,
                                           unsigned int maxNumWrites,
                                           unsigned int stackSizeKB) {
  readerThreads_ = readerThreads;
  writerThreads_ = writerThreads;
  maxNumReads_ = maxNumReads;
  maxNumWrites_ = maxNumWrites;
  stackSize_ = stackSizeKB * 1024;

  if ((maxNumReads > 0 && maxNumWrites == 0) ||
      (maxNumReads == 0 && maxNumWrites > 0)) {
    throw std::invalid_argument(
        "maxNumReads and maxNumWrites should be both 0 or both >0");
  }

  // Limit the fiber stack size to 1MB to prevent any misconfiguration;
  // The 1MB is too large for most use cases and there will be
  // lots of memory amounts to >800MB per thread wasted
  if (stackSizeKB >= 1024) {
    throw std::invalid_argument(
        "Maximum fiber stack size for each thread should be less than 1024 KB");
  }

  if (maxNumReads > 0 || maxNumWrites > 0) {
    if ((maxNumReads % readerThreads_) || (maxNumWrites % writerThreads_)) {
      throw std::invalid_argument(folly::sformat(
          "reader threads ({}) and writer threads ({}) should divide evenly "
          "into maxNumReads ({}) or maxNumWrites ({})",
          readerThreads_, writerThreads_, maxNumReads, maxNumWrites));
    }
  }

  if (!qDepth_) {
    // Adjust the device qdepth and enable async IO if needed
    qDepth_ =
        std::max(maxNumReads_ / readerThreads_, maxNumWrites_ / writerThreads_);
    if (qDepth_ > 0) {
      XDCHECK_EQ(ioEngine_, IoEngine::Sync);
      // TODO: default to libaio until T182829130 is fixed
      ioEngine_ = IoEngine::LibAio;
    }
  }
}

void NavyConfig::setReaderAndWriterThreads(uint32_t readerThreads,
                                           uint32_t writerThreads) {