Ref implementation : c_runtime_api.h

srkreddy1238 · July 3, 2018, 3:30pm

Is there a ref C implementation for this interface (or tutorial)?

masahi · July 4, 2018, 5:11am

you mean this?

dmlc/tvm/blob/master/src/runtime/c_runtime_api.cc

/*!
 *  Copyright (c) 2016 by Contributors
 * \file c_runtime_api.cc
 * \brief Device specific implementations
 */
#include <dmlc/thread_local.h>
#include <tvm/runtime/c_runtime_api.h>
#include <tvm/runtime/c_backend_api.h>
#include <tvm/runtime/packed_func.h>
#include <tvm/runtime/module.h>
#include <tvm/runtime/registry.h>
#include <tvm/runtime/device_api.h>
#ifdef _LIBCPP_SGX_CONFIG
#include "sgx/trusted/runtime.h"
#endif
#include <array>
#include <algorithm>
#include <string>
#include <cstdlib>
#include "./runtime_base.h"

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srkreddy1238 · July 4, 2018, 5:38am

sorry, i need to correct my question.
I mean the c application that use this interface to load a compiled tvm module and infer.

Java JNI is the closest one I see as of now.
Wanted to check if there is any other.

masahi · July 4, 2018, 6:00am

github.com

dmlc/tvm/blob/master/apps/howto_deploy/cpp_deploy.cc

/*!
 *  Copyright (c) 2017 by Contributors
 * \brief Example code on load and run TVM module.s
 * \file cpp_deploy_example.cc
 */
#include <cstdio>
#include <dlpack/dlpack.h>
#include <tvm/runtime/module.h>
#include <tvm/runtime/registry.h>
#include <tvm/runtime/packed_func.h>

void Verify(tvm::runtime::Module mod, std::string fname) {
  // Get the function from the module.
  tvm::runtime::PackedFunc f = mod.GetFunction(fname);
  CHECK(f != nullptr);
  // Allocate the DLPack data structures.
  //
  // Note that we use TVM runtime API to allocate the DLTensor in this example.
  // TVM accept DLPack compatible DLTensors, so function can be invoked
  // as long as we pass correct pointer to DLTensor array.

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srkreddy1238 · July 4, 2018, 6:38am

I know this. It use only TVMArrayAlloc from that interface.

masahi · July 4, 2018, 7:01am

I use C API at work. From that header I only use TVMArrayAlloc, TVMArrayCopyFromBytes, and TVMArrayCopyToBytes. For doing inference these are sufficient.

Other functions are used by LLVM CPU host codegen. The C runtime functions are directly embedded in LLVM IR. See for example https://github.com/dmlc/tvm/blob/master/src/codegen/llvm/codegen_cpu.cc#L88

srkreddy1238 · July 5, 2018, 6:49am

Thanks for the pointer. After some effort aroungd JNI reference I figured out the details now.