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CompareFlat.cu
1 /**
2 * Copyright (c) 2015-present, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under the BSD+Patents license found in the
6 * LICENSE file in the root directory of this source tree.
7 */
8
9
10 #include "../../IndexFlat.h"
11 #include "../../utils.h"
12 #include "../GpuIndexFlat.h"
13 #include "IndexWrapper.h"
14 #include "../test/TestUtils.h"
15 #include "../utils/DeviceTensor.cuh"
16 #include "../utils/DeviceUtils.h"
17 #include "../utils/HostTensor.cuh"
18 #include "../utils/Timer.h"
19 #include <gflags/gflags.h>
20 #include <map>
21 #include <memory>
22 #include <vector>
23
24 #include <cuda_profiler_api.h>
25
26 DEFINE_int32(k, 3, "final number of closest results returned");
27 DEFINE_int32(num, 128, "# of vecs");
28 DEFINE_int32(dim, 128, "# of dimensions");
29 DEFINE_int32(num_queries, 3, "number of query vectors");
30 DEFINE_bool(diff, true, "show exact distance + index output discrepancies");
31 DEFINE_bool(use_float16, false, "use encodings in float16");
32 DEFINE_bool(use_float16_math, false, "perform math in float16");
33 DEFINE_bool(transposed, false, "store vectors transposed");
34 DEFINE_int64(seed, -1, "specify random seed");
35 DEFINE_int32(num_gpus, 1, "number of gpus to use");
36 DEFINE_int64(pinned_mem, 0, "pinned memory allocation to use");
37 DEFINE_bool(cpu, true, "run the CPU code for timing and comparison");
38 DEFINE_bool(use_unified_mem, false, "use Pascal unified memory for the index");
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::IndexFlatL2>(
53 new faiss::IndexFlatL2(FLAGS_dim));
54
55 HostTensor<float, 2, true> vecs({FLAGS_num, FLAGS_dim});
56 faiss::float_rand(vecs.data(), vecs.numElements(), seed);
57
58 index->add(FLAGS_num, vecs.data());
59
60 printf("Database: dim %d num vecs %d\n", FLAGS_dim, FLAGS_num);
61 printf("L2 lookup: %d queries, total k %d\n",
62 numQueries, FLAGS_k);
63 printf("float16 encoding %s\n", FLAGS_use_float16 ? "enabled" : "disabled");
64 printf("transposed storage %s\n", FLAGS_transposed ? "enabled" : "disabled");
65
66 // Convert to GPU index
67 printf("Copying index to %d GPU(s)...\n", FLAGS_num_gpus);
68
69 auto initFn = [&index](faiss::gpu::GpuResources* res, int dev) ->
70 std::unique_ptr<faiss::gpu::GpuIndexFlatL2> {
71 ((faiss::gpu::StandardGpuResources*) res)->setPinnedMemory(
72 FLAGS_pinned_mem);
73
74 GpuIndexFlatConfig config;
75 config.device = dev;
76 config.useFloat16 = FLAGS_use_float16;
77 config.useFloat16Accumulator = FLAGS_use_float16_math;
78 config.storeTransposed = FLAGS_transposed;
79 config.memorySpace = FLAGS_use_unified_mem ?
80 MemorySpace::Unified : MemorySpace::Device;
81
82 auto p = std::unique_ptr<faiss::gpu::GpuIndexFlatL2>(
83 new faiss::gpu::GpuIndexFlatL2(res, index.get(), config));
84 return p;
85 };
86
87 IndexWrapper<faiss::gpu::GpuIndexFlatL2> gpuIndex(FLAGS_num_gpus, initFn);
88 printf("copy done\n");
89
90 // Build query vectors
91 HostTensor<float, 2, true> cpuQuery({numQueries, FLAGS_dim});
92 faiss::float_rand(cpuQuery.data(), cpuQuery.numElements(), seed);
93
94 // Time faiss CPU
95 HostTensor<float, 2, true> cpuDistances({numQueries, FLAGS_k});
96 HostTensor<faiss::Index::idx_t, 2, true> cpuIndices({numQueries, FLAGS_k});
97
98 if (FLAGS_cpu) {
99 float cpuTime = 0.0f;
100
101 CpuTimer timer;
102 index->search(numQueries,
103 cpuQuery.data(),
104 FLAGS_k,
105 cpuDistances.data(),
106 cpuIndices.data());
107
108 cpuTime = timer.elapsedMilliseconds();
109 printf("CPU time %.3f ms\n", cpuTime);
110 }
111
112 HostTensor<float, 2, true> gpuDistances({numQueries, FLAGS_k});
113 HostTensor<faiss::Index::idx_t, 2, true> gpuIndices({numQueries, FLAGS_k});
114
115 CUDA_VERIFY(cudaProfilerStart());
116 faiss::gpu::synchronizeAllDevices();
117
118 float gpuTime = 0.0f;
119
120 // Time GPU
121 {
122 CpuTimer timer;
123
124 gpuIndex.getIndex()->search(cpuQuery.getSize(0),
125 cpuQuery.data(),
126 FLAGS_k,
127 gpuDistances.data(),
128 gpuIndices.data());
129
130 // There is a device -> host copy above, so no need to time
131 // additional synchronization with the GPU
132 gpuTime = timer.elapsedMilliseconds();
133 }
134
135 CUDA_VERIFY(cudaProfilerStop());
136 printf("GPU time %.3f ms\n", gpuTime);
137
138 if (FLAGS_cpu) {
139 compareLists(cpuDistances.data(), cpuIndices.data(),
140 gpuDistances.data(), gpuIndices.data(),
141 numQueries, FLAGS_k,
142 "", true, FLAGS_diff, false);
143 }
144
145 CUDA_VERIFY(cudaDeviceSynchronize());
146
147 return 0;
148 }
faiss::gpu::CpuTimer::elapsedMilliseconds
float elapsedMilliseconds()
Returns elapsed time in milliseconds.
Definition: Timer.cpp:51
faiss::gpu::GpuIndexFlatConfig::useFloat16Accumulator
bool useFloat16Accumulator
Definition: GpuIndexFlat.h:39
faiss::gpu::GpuIndexFlatConfig::storeTransposed
bool storeTransposed
Definition: GpuIndexFlat.h:47
faiss::IndexFlatL2
Definition: IndexFlat.h:78
faiss::gpu::GpuResources
Definition: GpuResources.h:22
faiss::gpu::CpuTimer
CPU wallclock elapsed timer.
Definition: Timer.h:41
faiss::gpu::GpuIndexFlatConfig::useFloat16
bool useFloat16
Whether or not data is stored as float16.
Definition: GpuIndexFlat.h:34
faiss::gpu::GpuIndexConfig::device
int device
GPU device on which the index is resident.
Definition: GpuIndex.h:26
faiss::gpu::GpuIndexFlatConfig
Definition: GpuIndexFlat.h:26
faiss::gpu::GpuIndexConfig::memorySpace
MemorySpace memorySpace
Definition: GpuIndex.h:31
faiss::gpu::StandardGpuResources
Definition: StandardGpuResources.h:22
faiss::gpu::GpuIndexFlatL2
Definition: GpuIndexFlat.h:169
faiss::gpu::HostTensor
Definition: HostTensor.cuh:21
faiss::gpu::IndexWrapper
Definition: IndexWrapper.h:24