LimeSuiteNG: How to set FIFO size?

ricardas · 28 September 2025 22:09

LimeSuiteNG automatically sets up FIFO sizes based on sampling rates, to hold maximum of 250ms of data

src/streaming/TRXLooper.cpp

33d5a94c4


      
          mRxArgs.bufferSize = dmaBufferSize;
          mRxArgs.packetSize = packetSize;
          mRxArgs.packetsToBatch = mRx.packetsToBatch;
          mRxArgs.samplesInPacket = mRx.samplesInPkt;
          
          assert(mRxArgs.bufferSize > 0);
          assert(mRxArgs.packetSize > 0);
          assert(mRxArgs.packetsToBatch > 0);
          assert(mRxArgs.samplesInPacket > 0);
          
          const int packetsInFIFO = 0.25 * mConfig.hintSampleRate / mRx.samplesInPkt; // buffer 0.25 second of data
          mRx.packetsPool = std::make_unique<PacketsFIFO<StreamPacket*>>(packetsInFIFO);
          const uint32_t userSampleSize = mConfig.format == DataFormat::F32 ? sizeof(lime::complex32f_t) : sizeof(lime::complex16_t);
          for (uint32_t i = 0; i < mRx.packetsPool->max_size(); ++i)
              mRx.packetsPool->push(new StreamPacket(mRx.samplesInPkt, chCount, userSampleSize));
          mRx.fifo = std::make_unique<PacketsFIFO<StreamPacket*>>(packetsInFIFO);
          
          char msg[256];
          std::snprintf(msg,
              sizeof(msg),
              "%s Rx%i Setup: usePoll:%i rxSamplesInPkt:%i rxPacketsInBatch:%i, DMA_ReadSize:%i, link:%s, batchSizeInTime:%gus FS:%f, "

github.com/myriadrf/LimeSuiteNG

src/streaming/TRXLooper.cpp

33d5a94c4


      
                  chipId,
                  mTx.samplesInPkt,
                  mTx.packetsToBatch,
                  bufferTimeDuration * 1e6);
              if (showStats)
                  printf("%s\n", msg);
              if (mCallback_logMessage)
                  mCallback_logMessage(LogLevel::Verbose, msg);
          }
          
          const int packetsInFIFO = 0.25 * mConfig.hintSampleRate / (mTx.packetsToBatch * mTx.samplesInPkt); // buffer 0.25 second of data
          mTx.packetsPool = std::make_unique<PacketsFIFO<StreamPacket*>>(packetsInFIFO);
          const uint32_t userSampleSize = mConfig.format == DataFormat::F32 ? sizeof(lime::complex32f_t) : sizeof(lime::complex16_t);
          for (uint32_t i = 0; i < mTx.packetsPool->max_size(); ++i)
              mTx.packetsPool->push(new StreamPacket(mTx.packetsToBatch * mTx.samplesInPkt, chCount, userSampleSize));
          mTx.fifo = std::make_unique<PacketsFIFO<StreamPacket*>>(packetsInFIFO);
          
          mTx.terminate.store(false, std::memory_order_relaxed);
          mTx.terminateWorker.store(false, std::memory_order_relaxed);
          auto TxLoopFunction = std::bind(&TRXLooper::TxWorkLoop, this);

and aim for data latency of ~100us: LimeSuiteNG/src/streaming/TRXLooper.cpp at 33d5a94c4e3962b6ea1b5d9677a250f796e1658f · myriadrf/LimeSuiteNG · GitHub

The software performance difference between legacy LimeSuite and LimeSuiteNG is fixed now: LimeMini Maximum stable USB3 Rate? - #6 by ricardas

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LimeSuiteNG: How to set FIFO size?

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