Method processReq

cachelib/cachebench/workload/BlockChunkCache.cpp:314–387

}

bool BlockChunkCacheAdapter::processReq(BlockReqWrapper& rw,
                                        OpResultType result) {
  // We are only done if we have got everything.
  bool done = false;
  if (result == OpResultType::kGetHit || result == OpResultType::kSetSuccess ||
      result == OpResultType::kSetFailure || result == OpResultType::kSetSkip) {
    // Update the piece fetch index
    rw.cachePieces->updateFetchIndex();

    // The piece index we need to fetch next
    auto nextPieceIndex = rw.cachePieces->getCurFetchingPieceIndex();

    // Record the cache hit stats
    if (result == OpResultType::kGetHit) {
      auto resultPieceIndex = nextPieceIndex - 1;
      // We always fetch a complete piece.
      auto pieceSize = rw.cachePieces->getSizeOfAPiece(resultPieceIndex);
      stats_.recordPieceBodyHit(pieceSize);
    }

    // Check if we have got all the pieces we need to fetch
    if (rw.cachePieces->isPieceWithinBound(nextPieceIndex)) {
      XDCHECK_LT(nextPieceIndex, maxCachePieces_);
      // Reset op since it could have been changed to kSet
      rw.req.setOp(rw.op);
      // Update the piece key and the size
      rw.updatePieceKey(
          ChunkPieces::createPieceKey(rw.baseKey, nextPieceIndex));
      XDCHECK_EQ(rw.sizes.size(), 1u);
      rw.sizes[0] = rw.cachePieces->getSizeOfAPiece(nextPieceIndex);
    } else {
      // we are done
      done = true;
    }
  } else if (result == OpResultType::kGetMiss) {
    // We do the lookaside always, so perform set operation next
    // for the current piece
    rw.req.setOp(OpType::kSet);
    auto curIndex = rw.cachePieces->getCurFetchingPieceIndex() - 1;
    // Update the missing piece index accordingly
    if (rw.missPieceRange.first < 0) {
      rw.missPieceRange.first = curIndex;
    }
    rw.missPieceRange.second = curIndex;
  } else {
    XLOG(INFO) << "Unsupported OpResultType: " << static_cast<int>(result);
    done = true;
  }

  if (done && rw.op == OpType::kGet) {
    // We have got all the pieces that are requested, record the full
    if (rw.missPieceRange.first < 0) {
      // No missing pieces, record full hit
      stats_.recordRequestHit(rw.cachePieces->getTotalSize());
    } else {
      // Record ingress bytes since we will fetch the bytes from upstream.
      // Note that we always fetch all the missing pieces as one operation,
      // meaning any hit pieces in the middle will also be fetched again