GatedStokesSpectrometer.cu 25.9 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
#include "psrdada_cpp/effelsberg/edd/GatedStokesSpectrometer.cuh"
#include "psrdada_cpp/effelsberg/edd/Tools.cuh"
#include "psrdada_cpp/common.hpp"
#include "psrdada_cpp/cuda_utils.hpp"
#include "psrdada_cpp/raw_bytes.hpp"

#include <cuda.h>
#include <cuda_profiler_api.h>
#include <thrust/system/cuda/execution_policy.h>

#include <iostream>
#include <iomanip>
#include <cstring>
#include <sstream>

namespace psrdada_cpp {
namespace effelsberg {
namespace edd {

// Reduce thread local vatiable v in shared array x, so that x[0]
template<typename T>
__device__ void sum_reduce(T *x, const T &v)
{
  x[threadIdx.x] = v;
  __syncthreads();
  for(int s = blockDim.x / 2; s > 0; s = s / 2)
  {
    if (threadIdx.x < s)
      x[threadIdx.x] += x[threadIdx.x + s];
    __syncthreads();
  }
}


// If one of the side channel items is lsot, then both are considered as lost
// here
__global__ void mergeSideChannels(uint64_t* __restrict__ A, uint64_t* __restrict__ B, size_t N)
{
  for (size_t i = blockIdx.x * blockDim.x + threadIdx.x; (i < N);
       i += blockDim.x * gridDim.x)
  {
    uint64_t v = A[i] || B[i];
    A[i] = v;
    B[i] = v;
  }
}


__global__ void gating(float* __restrict__ G0,
        float* __restrict__ G1,
        const uint64_t* __restrict__ sideChannelData,
        size_t N, size_t heapSize, size_t bitpos,
        size_t noOfSideChannels, size_t selectedSideChannel,
        const float*  __restrict__ _baseLineG0,
        const float*  __restrict__ _baseLineG1,
        float* __restrict__ baseLineNG0,
        float* __restrict__ baseLineNG1,
        uint64_cu* stats_G0, uint64_cu* stats_G1) {
  // statistics values for samopels to G0, G1
  uint32_t _G0stats = 0;
  uint32_t _G1stats = 0;

  const float baseLineG0 = _baseLineG0[0];
  const float baseLineG1 = _baseLineG1[0];

  float baselineUpdateG0 = 0;
  float baselineUpdateG1 = 0;

  for (size_t i = blockIdx.x * blockDim.x + threadIdx.x; (i < N);
       i += blockDim.x * gridDim.x) {
    const float v = G0[i];

    const uint64_t sideChannelItem = sideChannelData[((i / heapSize) * (noOfSideChannels)) +
                        selectedSideChannel];

    const unsigned int bit_set = TEST_BIT(sideChannelItem, bitpos);
    const unsigned int heap_lost = TEST_BIT(sideChannelItem, 63);
    G1[i] = (v - baseLineG1) * bit_set * (!heap_lost) + baseLineG1;
    G0[i] = (v - baseLineG0) * (!bit_set) *(!heap_lost) + baseLineG0;

    _G0stats += (!bit_set) *(!heap_lost);
    _G1stats += bit_set * (!heap_lost);

    baselineUpdateG1 += v * bit_set * (!heap_lost);
    baselineUpdateG0 += v * (!bit_set) *(!heap_lost);
  }

  __shared__ uint32_t x[1024];

  // Reduce G0, G1
  sum_reduce<uint32_t>(x, _G0stats);
  if(threadIdx.x == 0) {
    atomicAdd(stats_G0,  (uint64_cu) x[threadIdx.x]);
  }
  __syncthreads();

  sum_reduce<uint32_t>(x, _G1stats);
  if(threadIdx.x == 0) {
    atomicAdd(stats_G1,  (uint64_cu) x[threadIdx.x]);
  }
  __syncthreads();

  //reuse shared array
  float *y = (float*) x;
  //update the baseline array
  sum_reduce<float>(y, baselineUpdateG0);
  if(threadIdx.x == 0) {
    atomicAdd(baseLineNG0, y[threadIdx.x]);
  }
  __syncthreads();

  sum_reduce<float>(y, baselineUpdateG1);
  if(threadIdx.x == 0) {
    atomicAdd(baseLineNG1, y[threadIdx.x]);
  }
  __syncthreads();
}



// Updates the baselines of the gates for the polarization set for the next
// block
// only few output blocks per input block thus execution on only one thread.
// Important is that the execution is async on the GPU.
__global__ void update_baselines(float*  __restrict__ baseLineG0,
        float*  __restrict__ baseLineG1,
        float* __restrict__ baseLineNG0,
        float* __restrict__ baseLineNG1,
        uint64_cu* stats_G0, uint64_cu* stats_G1,
        size_t N)
{
    size_t NG0 = 0;
    size_t NG1 = 0;

    for (size_t i =0; i < N; i++)
    {
       NG0 += stats_G0[i];
       NG1 += stats_G1[i];
    }

    baseLineG0[0] = baseLineNG0[0] / NG0;
    baseLineG1[0] = baseLineNG1[0] / NG1;
    baseLineNG0[0] = 0;
    baseLineNG1[0] = 0;
}





template <class HandlerType>
GatedStokesSpectrometer<HandlerType>::GatedStokesSpectrometer(
    const DadaBufferLayout &dadaBufferLayout,
    std::size_t selectedSideChannel, std::size_t selectedBit, std::size_t fft_length, std::size_t naccumulate,
    std::size_t nbits, float input_level, float output_level,
    HandlerType &handler) : _dadaBufferLayout(dadaBufferLayout),
      _selectedSideChannel(selectedSideChannel), _selectedBit(selectedBit),
      _fft_length(fft_length),
      _naccumulate(naccumulate), _nbits(nbits), _handler(handler), _fft_plan(0),
      _call_count(0), _nsamps_per_heap(4096), _processing_efficiency(0.){

  // Sanity checks
  assert(((_nbits == 12) || (_nbits == 8)));
  assert(_naccumulate > 0);

  // check for any device errors
  CUDA_ERROR_CHECK(cudaDeviceSynchronize());

  BOOST_LOG_TRIVIAL(info)
      << "Creating new GatedStokesSpectrometer instance with parameters: \n"
      << "  fft_length           " << _fft_length << "\n"
      << "  naccumulate          " << _naccumulate << "\n"
      << "  nSideChannels        " << _dadaBufferLayout.getNSideChannels() << "\n"
      << "  speadHeapSize        " << _dadaBufferLayout.getHeapSize() << " byte\n"
      << "  selectedSideChannel  " << _selectedSideChannel << "\n"
      << "  selectedBit          " << _selectedBit << "\n"
      << "  output bit depth     " << sizeof(IntegratedPowerType) * 8;

  assert((_dadaBufferLayout.getNSideChannels() == 0) ||
         (selectedSideChannel < _dadaBufferLayout.getNSideChannels()));  // Sanity check of side channel value
  assert(selectedBit < 64); // Sanity check of selected bit

   _nsamps_per_buffer = _dadaBufferLayout.sizeOfData() * 8 / nbits;

  _nsamps_per_output_spectra = fft_length * naccumulate;
  int nBlocks;
  if (_nsamps_per_output_spectra <= _nsamps_per_buffer)
  { // one buffer block is used for one or multiple output spectra
    size_t N = _nsamps_per_buffer / _nsamps_per_output_spectra;
    // All data in one block has to be used
    assert(N * _nsamps_per_output_spectra == _nsamps_per_buffer);
    nBlocks = 1;
  }
  else
  { // multiple blocks are integrated intoone output
    size_t N =  _nsamps_per_output_spectra /  _nsamps_per_buffer;
    // All data in multiple blocks has to be used
    assert(N * _nsamps_per_buffer == _nsamps_per_output_spectra);
    nBlocks = N;
  }
  BOOST_LOG_TRIVIAL(debug) << "Integrating  " << _nsamps_per_output_spectra << " samples from " << nBlocks << " into one spectra.";

  _nchans = _fft_length / 2 + 1;
  int batch = _nsamps_per_buffer / _fft_length;
  float dof = 2 * _naccumulate;
  float scale =
      std::pow(input_level * std::sqrt(static_cast<float>(_nchans)), 2);
  float offset = scale * dof;
  float scaling = scale * std::sqrt(2 * dof) / output_level;
  BOOST_LOG_TRIVIAL(debug)
      << "Correction factors for 8-bit conversion: offset = " << offset
      << ", scaling = " << scaling;

  BOOST_LOG_TRIVIAL(debug) << "Generating FFT plan";
  int n[] = {static_cast<int>(_fft_length)};
  CUFFT_ERROR_CHECK(cufftPlanMany(&_fft_plan, 1, n, NULL, 1, _fft_length, NULL,
                                  1, _nchans, CUFFT_R2C, batch));
  cufftSetStream(_fft_plan, _proc_stream);

  BOOST_LOG_TRIVIAL(debug) << "Allocating memory";
  polarization0._raw_voltage.resize(_dadaBufferLayout.sizeOfData() / sizeof(uint64_t));
  polarization1._raw_voltage.resize(_dadaBufferLayout.sizeOfData() / sizeof(uint64_t));
  polarization0._sideChannelData.resize(_dadaBufferLayout.getNSideChannels() * _dadaBufferLayout.getNHeaps());
  polarization1._sideChannelData.resize(_dadaBufferLayout.getNSideChannels() * _dadaBufferLayout.getNHeaps());
  BOOST_LOG_TRIVIAL(debug) << "  Input voltages size (in 64-bit words): "
                           << polarization0._raw_voltage.size();
  _unpacked_voltage_G0.resize(_nsamps_per_buffer);
  _unpacked_voltage_G1.resize(_nsamps_per_buffer);

  BOOST_LOG_TRIVIAL(debug) << "  Unpacked voltages size (in samples): "
                           << _unpacked_voltage_G0.size();
232
233
  polarization0.resize(_nchans * batch);
  polarization1.resize(_nchans * batch);
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
  BOOST_LOG_TRIVIAL(debug) << "  Channelised voltages size: "
                           << polarization0._channelised_voltage_G0.size();

   stokes_G0.resize(_nchans, batch / (_naccumulate / nBlocks));
   stokes_G1.resize(_nchans, batch / (_naccumulate / nBlocks));

  // on the host full output is stored together with sci data in one buffer
  _host_power_db.resize( 8 * (_nchans * sizeof(IntegratedPowerType) + sizeof(size_t)) * batch / (_naccumulate / nBlocks));

  CUDA_ERROR_CHECK(cudaStreamCreate(&_h2d_stream));
  CUDA_ERROR_CHECK(cudaStreamCreate(&_proc_stream));
  CUDA_ERROR_CHECK(cudaStreamCreate(&_d2h_stream));
  CUFFT_ERROR_CHECK(cufftSetStream(_fft_plan, _proc_stream));

  _unpacker.reset(new Unpacker(_proc_stream));
} // constructor



template <class HandlerType>
GatedStokesSpectrometer<HandlerType>::~GatedStokesSpectrometer() {
  BOOST_LOG_TRIVIAL(debug) << "Destroying GatedStokesSpectrometer";
  if (!_fft_plan)
    cufftDestroy(_fft_plan);
  cudaStreamDestroy(_h2d_stream);
  cudaStreamDestroy(_proc_stream);
  cudaStreamDestroy(_d2h_stream);
}



template <class HandlerType>
void GatedStokesSpectrometer<HandlerType>::init(RawBytes &block) {
  BOOST_LOG_TRIVIAL(debug) << "GatedStokesSpectrometer init called";
  std::stringstream headerInfo;
  headerInfo << "\n"
      << "# Gated spectrometer parameters: \n"
      << "fft_length               " << _fft_length << "\n"
      << "nchannels                " << _fft_length << "\n"
      << "naccumulate              " << _naccumulate << "\n"
      << "selected_side_channel    " << _selectedSideChannel << "\n"
      << "selected_bit             " << _selectedBit << "\n"
      << "output_bit_depth         " << sizeof(IntegratedPowerType) * 8;

  size_t bEnd = std::strlen(block.ptr());
  if (bEnd + headerInfo.str().size() < block.total_bytes())
  {
    std::strcpy(block.ptr() + bEnd, headerInfo.str().c_str());
  }
  else
  {
    BOOST_LOG_TRIVIAL(warning) << "Header of size " << block.total_bytes()
      << " bytes already contains " << bEnd
      << "bytes. Cannot add gated spectrometer info of size "
      << headerInfo.str().size() << " bytes.";
  }

  _handler.init(block);
}



template <class HandlerType>
void GatedStokesSpectrometer<HandlerType>::gated_fft(
        PolarizationData &data,
  thrust::device_vector<uint64_cu> &_noOfBitSetsIn_G0,
  thrust::device_vector<uint64_cu> &_noOfBitSetsIn_G1
        )
{
  BOOST_LOG_TRIVIAL(debug) << "Unpacking raw voltages";
  switch (_nbits) {
  case 8:
    _unpacker->unpack<8>(data._raw_voltage.b(), _unpacked_voltage_G0);
    break;
  case 12:
    _unpacker->unpack<12>(data._raw_voltage.b(), _unpacked_voltage_G0);
    break;
  default:
    throw std::runtime_error("Unsupported number of bits");
  }

  // Loop over outputblocks, for case of multiple output blocks per input block
  int step = data._sideChannelData.b().size() / _noOfBitSetsIn_G0.size();

  for (size_t i = 0; i < _noOfBitSetsIn_G0.size(); i++)
  { // ToDo: Should be in one kernel call
  gating<<<1024, 1024, 0, _proc_stream>>>(
      thrust::raw_pointer_cast(_unpacked_voltage_G0.data() + i * step * _nsamps_per_heap),
      thrust::raw_pointer_cast(_unpacked_voltage_G1.data() + i * step * _nsamps_per_heap),
      thrust::raw_pointer_cast(data._sideChannelData.b().data() + i * step),
      _unpacked_voltage_G0.size() / _noOfBitSetsIn_G0.size(),
      _dadaBufferLayout.getHeapSize(),
      _selectedBit,
      _dadaBufferLayout.getNSideChannels(),
      _selectedSideChannel,
      thrust::raw_pointer_cast(data._baseLineG0.data()),
      thrust::raw_pointer_cast(data._baseLineG1.data()),
      thrust::raw_pointer_cast(data._baseLineG0_update.data()),
      thrust::raw_pointer_cast(data._baseLineG1_update.data()),
      thrust::raw_pointer_cast(_noOfBitSetsIn_G0.data() + i),
      thrust::raw_pointer_cast(_noOfBitSetsIn_G1.data() + i)
      );
  }

    // only few output blocks per input block thus execution on only one thread.
    // Important is that the execution is async on the GPU.
    update_baselines<<<1,1,0, _proc_stream>>>(
        thrust::raw_pointer_cast(data._baseLineG0.data()),
        thrust::raw_pointer_cast(data._baseLineG1.data()),
        thrust::raw_pointer_cast(data._baseLineG0_update.data()),
        thrust::raw_pointer_cast(data._baseLineG1_update.data()),
        thrust::raw_pointer_cast(_noOfBitSetsIn_G0.data()),
        thrust::raw_pointer_cast(_noOfBitSetsIn_G1.data()),
        _noOfBitSetsIn_G0.size()
            );

  BOOST_LOG_TRIVIAL(debug) << "Performing FFT 1";
  UnpackedVoltageType *_unpacked_voltage_ptr =
      thrust::raw_pointer_cast(_unpacked_voltage_G0.data());
  ChannelisedVoltageType *_channelised_voltage_ptr =
      thrust::raw_pointer_cast(data._channelised_voltage_G0.data());
  CUFFT_ERROR_CHECK(cufftExecR2C(_fft_plan, (cufftReal *)_unpacked_voltage_ptr,
                                 (cufftComplex *)_channelised_voltage_ptr));

  BOOST_LOG_TRIVIAL(debug) << "Performing FFT 2";
  _unpacked_voltage_ptr = thrust::raw_pointer_cast(_unpacked_voltage_G1.data());
  _channelised_voltage_ptr = thrust::raw_pointer_cast(data._channelised_voltage_G1.data());
  CUFFT_ERROR_CHECK(cufftExecR2C(_fft_plan, (cufftReal *)_unpacked_voltage_ptr,
                                 (cufftComplex *)_channelised_voltage_ptr));

  CUDA_ERROR_CHECK(cudaStreamSynchronize(_proc_stream));
  BOOST_LOG_TRIVIAL(debug) << "Exit processing";
} // process


template <class HandlerType>
bool GatedStokesSpectrometer<HandlerType>::operator()(RawBytes &block) {
    ++_call_count;
    BOOST_LOG_TRIVIAL(debug) << "GatedStokesSpectrometer operator() called (count = "
                             << _call_count << ")";
    if (block.used_bytes() != _dadaBufferLayout.getBufferSize()) {
      // Stop on unexpected buffer size
      BOOST_LOG_TRIVIAL(error) << "Unexpected Buffer Size - Got "
                               << block.used_bytes() << " byte, expected "
                               << _dadaBufferLayout.getBufferSize() << " byte)";
      CUDA_ERROR_CHECK(cudaDeviceSynchronize());
      cudaProfilerStop();
      return true;
    }

    // Copy data to device
    CUDA_ERROR_CHECK(cudaStreamSynchronize(_h2d_stream));
    polarization0.swap();
    polarization1.swap();

    BOOST_LOG_TRIVIAL(debug) << "   block.used_bytes() = " <<
        block.used_bytes() << ", dataBlockBytes = " <<
        _dadaBufferLayout.sizeOfData() << "\n";

    // Copy the data with stride to the GPU:
    // CPU: P1P2P1P2P1P2 ...
    // GPU: P1P1P1 ... P2P2P2 ...
    // If this is a bottleneck the gating kernel could sort the layout out
    // during copy
    int heapsize_bytes = _nsamps_per_heap * _nbits / 8;
    CUDA_ERROR_CHECK(cudaMemcpy2DAsync(
      static_cast<void *>(polarization0._raw_voltage.a_ptr()),
        heapsize_bytes,
        static_cast<void *>(block.ptr()),
        2 * heapsize_bytes,
        heapsize_bytes, _dadaBufferLayout.sizeOfData() / heapsize_bytes/ 2,
        cudaMemcpyHostToDevice, _h2d_stream));

    CUDA_ERROR_CHECK(cudaMemcpy2DAsync(
      static_cast<void *>(polarization1._raw_voltage.a_ptr()),
        heapsize_bytes,
        static_cast<void *>(block.ptr()) + heapsize_bytes,
        2 * heapsize_bytes,
        heapsize_bytes, _dadaBufferLayout.sizeOfData() / heapsize_bytes/ 2,
        cudaMemcpyHostToDevice, _h2d_stream));

    CUDA_ERROR_CHECK(cudaMemcpy2DAsync(
        static_cast<void *>(polarization0._sideChannelData.a_ptr()),
        sizeof(uint64_t),
        static_cast<void *>(block.ptr() + _dadaBufferLayout.sizeOfData() + _dadaBufferLayout.sizeOfGap()),
        2 * sizeof(uint64_t),
        sizeof(uint64_t),
        _dadaBufferLayout.sizeOfSideChannelData() / 2 / sizeof(uint64_t),
        cudaMemcpyHostToDevice, _h2d_stream));

    CUDA_ERROR_CHECK(cudaMemcpy2DAsync(
        static_cast<void *>(polarization1._sideChannelData.a_ptr()),
        sizeof(uint64_t),
        static_cast<void *>(block.ptr() + _dadaBufferLayout.sizeOfData() + _dadaBufferLayout.sizeOfGap() + sizeof(uint64_t)),
        2 * sizeof(uint64_t),
        sizeof(uint64_t),
        _dadaBufferLayout.sizeOfSideChannelData() / 2 / sizeof(uint64_t), cudaMemcpyHostToDevice, _h2d_stream));

    BOOST_LOG_TRIVIAL(debug) << "First side channel item: 0x" <<   std::setw(16)
        << std::setfill('0') << std::hex <<
        (reinterpret_cast<uint64_t*>(block.ptr() + _dadaBufferLayout.sizeOfData()
                                     + _dadaBufferLayout.sizeOfGap()))[0] << std::dec;


  if (_call_count == 1) {
    return false;
  }

  // process data
  // check if new outblock is started:  _call_count -1 because this is the block number on the device
  bool newBlock = (((_call_count-1) * _nsamps_per_buffer) % _nsamps_per_output_spectra == 0);

  // only if  a newblock is started the output buffer is swapped. Otherwise the
  // new data is added to it
  if (newBlock)
  {
      BOOST_LOG_TRIVIAL(debug) << "Starting new output block.";
      stokes_G0.swap();
      stokes_G1.swap();
      stokes_G0.reset(_proc_stream);
      stokes_G1.reset(_proc_stream);
  }

  mergeSideChannels<<<1024, 1024, 0, _proc_stream>>>(thrust::raw_pointer_cast(polarization0._sideChannelData.a().data()),
          thrust::raw_pointer_cast(polarization1._sideChannelData.a().data()), polarization1._sideChannelData.a().size());

  gated_fft(polarization0, stokes_G0._noOfBitSets.a(), stokes_G1._noOfBitSets.a());
  gated_fft(polarization1, stokes_G0._noOfBitSets.a(), stokes_G1._noOfBitSets.a());

  stokes_accumulate<<<1024, 1024, 0, _proc_stream>>>(
          thrust::raw_pointer_cast(polarization0._channelised_voltage_G0.data()),
          thrust::raw_pointer_cast(polarization1._channelised_voltage_G0.data()),
          thrust::raw_pointer_cast(stokes_G0.I.a().data()),
          thrust::raw_pointer_cast(stokes_G0.Q.a().data()),
          thrust::raw_pointer_cast(stokes_G0.U.a().data()),
          thrust::raw_pointer_cast(stokes_G0.V.a().data()),
          _nchans, _naccumulate
          );

  stokes_accumulate<<<1024, 1024, 0, _proc_stream>>>(
          thrust::raw_pointer_cast(polarization0._channelised_voltage_G1.data()),
          thrust::raw_pointer_cast(polarization1._channelised_voltage_G1.data()),
          thrust::raw_pointer_cast(stokes_G1.I.a().data()),
          thrust::raw_pointer_cast(stokes_G1.Q.a().data()),
          thrust::raw_pointer_cast(stokes_G1.U.a().data()),
          thrust::raw_pointer_cast(stokes_G1.V.a().data()),
          _nchans, _naccumulate
          );


  CUDA_ERROR_CHECK(cudaStreamSynchronize(_proc_stream));

  if ((_call_count == 2) || (!newBlock)) {
    return false;
  }

  // copy data to host if block is finished
  CUDA_ERROR_CHECK(cudaStreamSynchronize(_d2h_stream));
  _host_power_db.swap();
  // OUTPUT MEMORY LAYOUT:
  // I G0, IG1,Q G0, QG1, U G0,UG1,V G0,VG1, 8xSCI, ...

  for (size_t i = 0; i < stokes_G0._noOfBitSets.size(); i++)
  {
    size_t memslicesize = (_nchans * sizeof(IntegratedPowerType));
    size_t memOffset = 8 * i * (memslicesize +  + sizeof(size_t));
    // Copy  II QQ UU VV
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset) ,
                        static_cast<void *>(stokes_G0.I.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 1 * memslicesize) ,
                        static_cast<void *>(stokes_G1.I.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 2 * memslicesize) ,
                        static_cast<void *>(stokes_G0.Q.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 3 * memslicesize) ,
                        static_cast<void *>(stokes_G1.Q.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 4 * memslicesize) ,
                        static_cast<void *>(stokes_G0.U.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 5 * memslicesize) ,
                        static_cast<void *>(stokes_G1.U.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 6 * memslicesize) ,
                        static_cast<void *>(stokes_G0.V.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    CUDA_ERROR_CHECK(
        cudaMemcpyAsync(static_cast<void *>(_host_power_db.a_ptr() + memOffset + 7 * memslicesize) ,
                        static_cast<void *>(stokes_G1.V.b_ptr() + i * memslicesize),
                        _nchans * sizeof(IntegratedPowerType),
                        cudaMemcpyDeviceToHost, _d2h_stream));

    // Copy SCI
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize),
          static_cast<void *>(stokes_G0._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 1 * sizeof(size_t)),
          static_cast<void *>(stokes_G1._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 2 * sizeof(size_t)),
          static_cast<void *>(stokes_G0._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 3 * sizeof(size_t)),
          static_cast<void *>(stokes_G1._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 4 * sizeof(size_t)),
          static_cast<void *>(stokes_G0._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 5 * sizeof(size_t)),
          static_cast<void *>(stokes_G1._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 6 * sizeof(size_t)),
          static_cast<void *>(stokes_G0._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));
    CUDA_ERROR_CHECK(
        cudaMemcpyAsync( static_cast<void *>(_host_power_db.a_ptr() + memOffset + 8 * memslicesize + 7 * sizeof(size_t)),
          static_cast<void *>(stokes_G1._noOfBitSets.b_ptr() + i ),
            1 * sizeof(size_t),
            cudaMemcpyDeviceToHost, _d2h_stream));

  }

  BOOST_LOG_TRIVIAL(debug) << "Copy Data back to host";

  if (_call_count == 3) {
    return false;
  }

  // calculate off value
  //BOOST_LOG_TRIVIAL(info) << "Buffer block: " << _call_count-3 << " with " << _noOfBitSetsIn_G0.size() << "x2 output heaps:";
  //size_t total_samples_lost = 0;
  //for (size_t i = 0; i < _noOfBitSetsIn_G0.size(); i++)
  //{
  //  size_t memOffset = 2 * i * (_nchans * sizeof(IntegratedPowerType) + sizeof(size_t));

  //  size_t* on_values = reinterpret_cast<size_t*> (_host_power_db.b_ptr() + memOffset + 2 * _nchans * sizeof(IntegratedPowerType));
  //  size_t* off_values = reinterpret_cast<size_t*> (_host_power_db.b_ptr() + memOffset + 2 * _nchans * sizeof(IntegratedPowerType) + sizeof(size_t));

  //  size_t samples_lost = _nsamps_per_output_spectra - (*on_values) - (*off_values);
  //  total_samples_lost += samples_lost;

  //  BOOST_LOG_TRIVIAL(info) << "    Heap " << i << ":\n"
  //    <<"                            Samples with  bit set  : " << *on_values << std::endl
  //    <<"                            Samples without bit set: " << *off_values << std::endl
  //    <<"                            Samples lost           : " << samples_lost << " out of " << _nsamps_per_output_spectra << std::endl;
  //}
  //double efficiency = 1. - double(total_samples_lost) / (_nsamps_per_output_spectra * _noOfBitSetsIn_G0.size());
  //double prev_average = _processing_efficiency / (_call_count- 3 - 1);
  //_processing_efficiency += efficiency;
  //double average = _processing_efficiency / (_call_count-3);
  //BOOST_LOG_TRIVIAL(info) << "Total processing efficiency of this buffer block:" << std::setprecision(6) << efficiency << ". Run average: " << average << " (Trend: " << std::showpos << (average - prev_average) << ")";

  // Wrap in a RawBytes object here;
  RawBytes bytes(reinterpret_cast<char *>(_host_power_db.b_ptr()),
                 _host_power_db.size(),
                 _host_power_db.size());
  BOOST_LOG_TRIVIAL(debug) << "Calling handler";
  // The handler can't do anything asynchronously without a copy here
  // as it would be unsafe (given that it does not own the memory it
  // is being passed).

  _handler(bytes);
  return false; //
} // operator ()

} // edd
} // effelsberg
} // psrdada_cpp