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CompareIVFFlat.cu
1 /**
2 * Copyright (c) 2015-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under the CC-by-NC license found in the
6 * LICENSE file in the root directory of this source tree.
7 */
8
9 // Copyright 2004-present Facebook. All Rights Reserved.
10
11 #include "../../IndexIVF.h"
12 #include "../../index_io.h"
13 #include "../../utils.h"
14
15 #include "../GpuIndexIVFFlat.h"
16 #include "IndexWrapper.h"
17 #include "../test/TestUtils.h"
18 #include "../utils/DeviceTensor.cuh"
19 #include "../utils/DeviceUtils.h"
20 #include "../utils/HostTensor.cuh"
21 #include "../utils/Timer.h"
22 #include <gflags/gflags.h>
23 #include <map>
24 #include <memory>
25 #include <vector>
26
27 #include <cuda_profiler_api.h>
28
29 DEFINE_int32(nprobe, 5, "number of coarse centroids to probe");
30 DEFINE_int32(k, 3, "final number of closest results returned");
31 DEFINE_int32(num_queries, 3, "number of query vectors");
32 DEFINE_string(in, "/home/jhj/local/index.out", "index file for input");
33 DEFINE_bool(diff, true, "show exact distance + index output discrepancies");
34 DEFINE_bool(use_float16, false, "use encodings in float16");
35 DEFINE_bool(use_float16_coarse, false, "coarse quantizer in float16");
36 DEFINE_int64(seed, -1, "specify random seed");
37 DEFINE_int32(num_gpus, 1, "number of gpus to use");
38 DEFINE_int32(index, 2, "0 = no indices on GPU; 1 = 32 bit, 2 = 64 bit on GPU");
39
40 using namespace faiss::gpu;
41
42 int main(int argc, char** argv) {
43 gflags::ParseCommandLineFlags(&argc, &argv, true);
44
45 cudaProfilerStop();
46
47 auto seed = FLAGS_seed != -1L ? FLAGS_seed : time(nullptr);
48 printf("using seed %ld\n", seed);
49
50 auto numQueries = FLAGS_num_queries;
51
52 auto index = std::unique_ptr<faiss::IndexIVFFlat>(
53 dynamic_cast<faiss::IndexIVFFlat*>(faiss::read_index(FLAGS_in.c_str())));
54 FAISS_ASSERT((bool) index);
55 index->nprobe = FLAGS_nprobe;
56
57 auto dim = index->d;
58
59 printf("Database: dim %d num vecs %ld\n", dim, index->ntotal);
60 printf("Coarse centroids: %ld\n", index->quantizer->ntotal);
61 printf("L2 lookup: %d queries, nprobe %d, total k %d\n",
62 numQueries, FLAGS_nprobe, FLAGS_k);
63 printf("float16 coarse quantizer %s\n",
64 FLAGS_use_float16_coarse ? "enabled" : "disabled");
65 printf("float16 encoding %s\n",
66 FLAGS_use_float16 ? "enabled" : "disabled");
67
68 // Convert to GPU index
69 printf("Copying index to %d GPU(s)...\n", FLAGS_num_gpus);
70
71 auto initFn = [&index](faiss::gpu::GpuResources* res, int dev) ->
72 std::unique_ptr<faiss::gpu::GpuIndexIVFFlat> {
73 GpuIndexIVFFlatConfig config;
74 config.device = dev;
75 config.indicesOptions = (faiss::gpu::IndicesOptions) FLAGS_index;
76 config.flatConfig.useFloat16 = FLAGS_use_float16_coarse;
77 config.useFloat16IVFStorage = FLAGS_use_float16;
78
79 auto p = std::unique_ptr<faiss::gpu::GpuIndexIVFFlat>(
80 new faiss::gpu::GpuIndexIVFFlat(res,
81 index->d,
82 index->nlist,
83 index->metric_type,
84 config));
85 p->copyFrom(index.get());
86 return p;
87 };
88
89 IndexWrapper<faiss::gpu::GpuIndexIVFFlat> gpuIndex(FLAGS_num_gpus, initFn);
90 gpuIndex.setNumProbes(FLAGS_nprobe);
91 printf("copy done\n");
92
93 // Build query vectors
94 HostTensor<float, 2, true> cpuQuery({numQueries, dim});
95 faiss::float_rand(cpuQuery.data(), cpuQuery.numElements(), seed);
96
97 // Time faiss CPU
98 HostTensor<float, 2, true> cpuDistances({numQueries, FLAGS_k});
99 HostTensor<faiss::Index::idx_t, 2, true> cpuIndices({numQueries, FLAGS_k});
100
101 float cpuTime = 0.0f;
102
103 {
104 CpuTimer timer;
105 index->search(numQueries,
106 cpuQuery.data(),
107 FLAGS_k,
108 cpuDistances.data(),
109 cpuIndices.data());
110
111 cpuTime = timer.elapsedMilliseconds();
112 }
113
114 printf("CPU time %.3f ms\n", cpuTime);
115
116 HostTensor<float, 2, true> gpuDistances({numQueries, FLAGS_k});
117 HostTensor<faiss::Index::idx_t, 2, true> gpuIndices({numQueries, FLAGS_k});
118
119 CUDA_VERIFY(cudaProfilerStart());
120 faiss::gpu::synchronizeAllDevices();
121
122 float gpuTime = 0.0f;
123
124 // Time GPU
125 {
126 CpuTimer timer;
127
128 gpuIndex.getIndex()->search(cpuQuery.getSize(0),
129 cpuQuery.data(),
130 FLAGS_k,
131 gpuDistances.data(),
132 gpuIndices.data());
133
134 // There is a device -> host copy above, so no need to time
135 // additional synchronization with the GPU
136 gpuTime = timer.elapsedMilliseconds();
137 }
138
139 CUDA_VERIFY(cudaProfilerStop());
140 printf("GPU time %.3f ms\n", gpuTime);
141
142 compareLists(cpuDistances.data(), cpuIndices.data(),
143 gpuDistances.data(), gpuIndices.data(),
144 numQueries, FLAGS_k,
145 "", true, FLAGS_diff, false);
146
147 CUDA_VERIFY(cudaDeviceSynchronize());
148 // printf("\ncudaMalloc usage %zd\n",
149 // resources.getMemoryManager().getHighWaterCudaMalloc());
150
151 return 0;
152 }
faiss::gpu::CpuTimer::elapsedMilliseconds
float elapsedMilliseconds()
Returns elapsed time in milliseconds.
Definition: Timer.cpp:52
faiss::read_index
Index * read_index(FILE *f, bool try_mmap)
Definition: index_io.cpp:536
faiss::gpu::GpuIndexIVFFlatConfig::useFloat16IVFStorage
bool useFloat16IVFStorage
Definition: GpuIndexIVFFlat.h:29
faiss::gpu::GpuResources
Definition: GpuResources.h:23
faiss::gpu::CpuTimer
CPU wallclock elapsed timer.
Definition: Timer.h:42
faiss::IndexIVFFlat
Definition: IndexIVF.h:132
faiss::gpu::GpuIndexFlatConfig::useFloat16
bool useFloat16
Whether or not data is stored as float16.
Definition: GpuIndexFlat.h:35
faiss::gpu::GpuIndexConfig::device
int device
GPU device on which the index is resident.
Definition: GpuIndex.h:27
faiss::gpu::GpuIndexIVFConfig::flatConfig
GpuIndexFlatConfig flatConfig
Configuration for the coarse quantizer object.
Definition: GpuIndexIVF.h:34
faiss::gpu::HostTensor
Definition: HostTensor.cuh:22
faiss::gpu::GpuIndexIVFFlatConfig
Definition: GpuIndexIVFFlat.h:22
faiss::gpu::GpuIndexIVFConfig::indicesOptions
IndicesOptions indicesOptions
Index storage options for the GPU.
Definition: GpuIndexIVF.h:31
faiss::gpu::GpuIndexIVFFlat
Definition: GpuIndexIVFFlat.h:34
faiss::gpu::IndexWrapper
Definition: IndexWrapper.h:25