Reading IR

Ascend GPU CPU Model Optimization

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Overview

When a model compiled using MindSpore runs in the graph mode context.set_context(mode=context.GRAPH_MODE) and context.set_context(save_graphs=True) is set in the configuration, some intermediate files will be generated during graph compliation. These intermediate files are called IR files. Currently, there are three IR files:

  • .ir file: An IR file that describes the model structure in text format and can be directly viewed using any text editors.

  • .dat file: An IR file that describes the model structure more strictly than the .ir file. It contains more contents and can be directly viewed using any text editors.

  • .dot file: An IR file that describes the topology relationships between different nodes. You can use this file by graphviz as the input to generate images for users to view the model structure. For models with multiple operators, it is recommended using the visualization component MindInsight to visualize computing graphs.

Saving IR

context.set_context(save_graphs=True) is used to save the intermediate code in each compilation phase. The intermediate code can be saved in two formats. One is the text format with the suffix .ir, and the other is the graphical format with the suffix .dot. When the network scale is small, you are advised to use the graphical format that is more intuitive. When the network scale is large, you are advised to use the text format that is more efficient.

You can run the graphviz command to convert a .dot file to the picture format. For example, you can run the dot -Tpng *.dot -o *.png command to convert a .dot file to a .png file.

Add the following code to train.py. When running the script, MindSpore will automatically store the IR files generated during compilation under the specified path.

if __name__ == "__main__":
    context.set_context(save_graphs=True, save_graphs_path="path/to/ir/files")

After the training command is executed, the following files are generated in the path of save_graphs_path: the IR files starting with digits and underscores are generated during the ME graph compilation. The compute graph is saved in each phase of the pipeline. Let’s see the important phases. For examples, the parse phase parses the construct function of the entrance. The symbol_resolve phase recursively parses other functions and objects directly or indirectly referenced by the entry function. The abstract_specialize phase, namely graph evaluate phase, data type derivation and shape derivation are performed. The optimize phase, hardware-independent optimization is performed, the automatic differential and automatic parallel functions are also performed. The validate phase, the compiled compute graph is verified. The task_emit phase, the computing graph is transferred to the backend for further processing. The calculation graph is executed in the execute phase.

.
├──00_parse_0000.dot
├──00_parse_0001.ir
├──00_parse_0002.dat
├──01_symbol_resolve_0003.dot
├──01_symbol_resolve_0004.ir
├──01_symbol_resolve_0005.dat
├──02_combine_like_graphs_0006.dot
├──02_combine_like_graphs_0007.ir
├──02_combine_like_graphs_0008.dat
├──03_inference_opt_prepare_0009.dot
├──03_inference_opt_prepare_0010.ir
├──03_inference_opt_prepare_0011.dat
├──04_abstract_specialize_0012.dot
├──04_abstract_specialize_0013.ir
├──04_abstract_specialize_0014.dat
...

IR File Contents Introduction

The following is an example to describe the contents of the IR file.

import mindspore.context as context
import mindspore.nn as nn
from mindspore import Tensor
from mindspore import ops
from mindspore import dtype as mstype

context.set_context(mode=context.GRAPH_MODE)
context.set_context(save_graphs=True, save_graphs_path="./")

class Net(nn.Cell):
    def __init__(self):
        super().__init__()
        self.add = ops.Add()
        self.sub = ops.Sub()
        self.mul = ops.Mul()
        self.div = ops.Div()

    def func(x, y):
        return self.div(x, y)

    def construct(self, x, y):
        a = self.sub(x, 1)
        b = self.add(a, y)
        c = self.mul(b, self.func(a, b))
        return c

input1 = Tensor(3, mstype.float32)
input2 = Tensor(2, mstype.float32)
net = Net()
out = net(input1, input2)
print(out)

ir Introduction

Use a text editing software (for example, vi) to open the 04_abstract_specialize_0013.ir file. The file contents are as follows:

  1 #IR entry      : @1_construct_wrapper.21
  2 #attrs         :
  3 #Total params  : 2
  4
  5 %para1_x : <Tensor[Float32]x()>
  6 %para2_y : <Tensor[Float32]x()>
  7
  8 #Total subgraph : 3
  9
 10 subgraph attr:
 11 Undeterminate : 0
 12 subgraph @2_construct.22(%para3_x, %para4_y) {
 13   %0(a) = Sub(%para3_x, Tensor(shape=[], dtype=Float32, value= 1)) {instance name: sub} primitive_attrs: {input_names: [x, y], output_names: [output]}
 14       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 15       # In file train.py(34)/        a = self.sub(x, 1)/
 16   %1(b) = Add(%0, %para4_y) {instance name: add} primitive_attrs: {input_names: [x, y], output_names: [output]}
 17       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 18       # In file train.py(35)/        b = self.add(a, y)/
 19   %2([CNode]5) = call @3_func.23(%0, %1)
 20       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 21       # In file train.py(36)/        c = self.mul(b, self.func(a, b))/
 22   %3(c) = Mul(%1, %2) {instance name: mul} primitive_attrs: {input_names: [x, y], output_names: [output]}
 23       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 24       # In file train.py(36)/        c = self.mul(b, self.func(a, b))/
 25   Return(%3)
 26       : (<Tensor[Float32]x()>)
 27       # In file train.py(37)/        return c/
 28 }
 29
 30 subgraph attr:
 31 Undeterminate : 0
 32 subgraph @3_func.23(%para5_x, %para6_y) {
 33   %0([CNode]20) = Div(%para5_x, %para6_y) {instance name: div} primitive_attrs: {input_names: [x, y], output_names: [output]}
 34       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 35       # In file train.py(31)/        return self.div(x, y)/
 36   Return(%0)
 37       : (<Tensor[Float32]x()>)
 38       # In file train.py(31)/        return self.div(x, y)/
 39 }
 40
 41 subgraph attr:
 42 subgraph @1_construct_wrapper.21() {
 43   %0([CNode]2) = call @2_construct.22(%para1_x, %para2_y)
 44       : (<Tensor[Float32]x()>, <Tensor[Float32]x()>) -> (<Tensor[Float32]x()>)
 45       # In file train.py(37)/        return c/
 46   Return(%0)
 47       : (<Tensor[Float32]x()>)
 48       # In file train.py(37)/        return c/
 49 }

The above contents can be divided into two parts, the first part is the input list and the second part is the graph structure. The first line tells us the name of the top MindSpore graph about the network, 1_construct_wrapper.21, or the entry graph. Line 3 tells us how many inputs are in the network. Line 5 to 6 are the input list, which is in the format of %para[No.]_[name] : <[data_type]x[shape]>. Line 8 tells us the number of subgraph parsed by the network. There are 3 graphs in this IR. Line 42 is the entry graph 1_construct_wrapper.21. Line 32 is graph 3_func.23, parsed from the func(x, y) in the source script. Line 12 is graph 2_construct.22, parsed from the function construct. Taking graph 2_construct.22 as an example, Line 10 to 28 indicate the graph structure, which contains several nodes, namely, CNode. In this example, there are Sub, Add, Mul. They are defined in the function __init__. Line 19 calls a graph by call @3_func.23. It indicates calling the graph func(x, y) to execute a division operation.

The ]CNode](https://www.mindspore.cn/docs/programming_guide/en/r1.5/design/mindir.html#syntax) information format is as follows: including the node name, attribute, input node, the specs of the inputs and outputs, and source code parsing call stack. The ANF graph is a unidirectional acyclic graph. So, the connection between nodes is displayed only based on the input relationship. The source code parsing call stack reflects the relationship between the CNode and the script source code. For example, line 15 is parsed from a = self.sub(x, 1).

  %[No.]([debug_name]) = [op_name]([arg], ...) primitive_attrs: {[key]: [value], ...}
      : (<[input data_type]x[input shape]>, ...) -> (<[output data_type]x[output shape]>, ...)
      # Call stack for source code parsing

After several optimizations by the compiler, the node may undergo several changes (such as operator splitting and operator merging). The source code parsing call stack information of the node may not be in a one-to-one correspondence with the script. This is only an auxiliary method.

dat Introduction

Use a text editing software (for example, vi) to open the 04_abstract_specialize_0014.dat file. The file contents are as follows:

  1 # [No.1] 1_construct_wrapper.21
  2 # In file train.py(33)/    def construct(self, x, y):/
  3 funcgraph fg_21(
  4         %para1 : Tensor(F32)[]    # x
  5         , %para2 : Tensor(F32)[]    # y
  6     ) {
  7     %1 : Tensor(F32)[] = FuncGraph::fg_22(%para1, %para2)    #(Tensor(F32)[], Tensor(F32)[])    # fg_22=2_construct.22 #scope: Default
  8       # In file train.py(37)/        return c/#[CNode]2
  9     Primitive::Return{prim_type=1}(%1)    #(Tensor(F32)[]) #scope: Default
 10       # In file train.py(37)/        return c/#[CNode]1
 11 }
 12 # order:
 13 #   1: 1_construct_wrapper.21:[CNode]2{[0]: ValueNode<FuncGraph> 2_construct.22, [1]: x, [2]: y}
 14 #   2: 1_construct_wrapper.21:[CNode]1{[0]: ValueNode<Primitive> Return, [1]: [CNode]2}
 15
 16
 17 # [No.2] 2_construct.22
 18 # In file train.py(33)/    def construct(self, x, y):/
 19 funcgraph fg_22(
 20         %para3 : Tensor(F32)[]    # x
 21         , %para4 : Tensor(F32)[]    # y
 22     ) {
 23     %1 : Tensor(F32)[] = PrimitivePy::Sub{prim_type=2}[input_names=["x", "y"], output_names=["output"]](%para3, Tensor(43)[])    #(Tensor(F32)[], Tenso    r(F32)[]) #scope: Default
 24       # In file train.py(34)/        a = self.sub(x, 1)/#a
 25     %2 : Tensor(F32)[] = PrimitivePy::Add{prim_type=2}[input_names=["x", "y"], output_names=["output"]](%1, %para4)    #(Tensor(F32)[], Tensor(F32)[])     #scope: Default
 26       # In file train.py(35)/        b = self.add(a, y)/#b
 27     %3 : Tensor(F32)[] = FuncGraph::fg_23(%1, %2)    #(Tensor(F32)[], Tensor(F32)[])    # fg_23=3_func.23 #scope: Default
 28       # In file train.py(36)/        c = self.mul(b, self.func(a, b))/#[CNode]5
 29     %4 : Tensor(F32)[] = PrimitivePy::Mul{prim_type=2}[input_names=["x", "y"], output_names=["output"]](%2, %3)    #(Tensor(F32)[], Tensor(F32)[]) #sco    pe: Default
 30       # In file train.py(36)/        c = self.mul(b, self.func(a, b))/#c
 31     Primitive::Return{prim_type=1}(%4)    #(Tensor(F32)[]) #scope: Default
 32       # In file train.py(37)/        return c/#[CNode]4
 33 }
 34 # order:
 35 #   1: 2_construct.22:a{[0]: ValueNode<PrimitivePy> Sub, [1]: x, [2]: ValueNode<Tensor> Tensor(shape=[], dtype=Float32, value= 1)}
 36 #   2: 2_construct.22:b{[0]: ValueNode<PrimitivePy> Add, [1]: a, [2]: y}
 37 #   3: 2_construct.22:[CNode]5{[0]: ValueNode<FuncGraph> 3_func.23, [1]: a, [2]: b}
 38 #   4: 2_construct.22:c{[0]: ValueNode<PrimitivePy> Mul, [1]: b, [2]: [CNode]5}
 39 #   5: 2_construct.22:[CNode]4{[0]: ValueNode<Primitive> Return, [1]: c}
 40
 41
 42 # [No.3] 3_func.23
 43 # In file train.py(30)/    def func(x, y):/
 44 funcgraph fg_23(
 45         %para5 : Tensor(F32)[]    # x
 46         , %para6 : Tensor(F32)[]    # y
 47     ) {
 48     %1 : Tensor(F32)[] = PrimitivePy::Div{prim_type=2}[input_names=["x", "y"], output_names=["output"]](%para5, %para6)    #(Tensor(F32)[], Tensor(F32)    []) #scope: Default
 49       # In file train.py(31)/        return self.div(x, y)/#[CNode]20
 50     Primitive::Return{prim_type=1}(%1)    #(Tensor(F32)[]) #scope: Default
 51       # In file train.py(31)/        return self.div(x, y)/#[CNode]19
 52 }
 53 # order:
 54 #   1: 3_func.23:[CNode]20{[0]: ValueNode<PrimitivePy> Div, [1]: x, [2]: y}
 55 #   2: 3_func.23:[CNode]19{[0]: ValueNode<Primitive> Return, [1]: [CNode]20}
 56
 57
 58 # num of total function graphs: 3

Above, it lists all the graphs beginning with the entry graph. Line 1 indicates graph 1_construct_wrapper.21 whose id is No.1. And line 7 calls graph 2_construct.22. line 17 to 39 shows the information of graph 2_construct.22. Taking graph 2_construct.22 as an example. Line 18 tells us which function this graph is parsed from. Line 20 to 21 indicates the input information which is in the format of %para[No.] : [data_type][shape]    # [name]. Line 23 to 32 indicates the graph structure, which contains several nodes, namely, CNode. In this example, there are Sub, Add, Mul. They are defined in the function __init__. Line 34 to 39 shows the execution order of the CNode from graph 2_construct.22, corresponding to the order of code execution. The information format is: No.: belonging graph:node name{[0]: the first input, [1]: the second input, ...}. For CNode, the first input indicates how to compute for this CNode. Line 28 indicates the number of graphs. Here is 3.

The CNode information format is as follows: including the node name, attribute, input node, output information, format, and source code parsing call stack.

%[No,] : [outputs' Spec] = [op_name]{[prim_type]}[attr0, attr1, ...](arg0, arg1, ...)    #(inputs' Spec)#[scope]
  # Call stack for source code parsing/#debug_name

Reading analyze_fail.dat

In the process of MindSpore compiling a graph, the exceptions about graph evaluating fail usually happen. But we can find the reason by analyzing the exception information and analyze_fail.dat.

For example, we run the script below.

  1 import mindspore.context as context
  2 import mindspore.nn as nn
  3 from mindspore import Tensor
  4 from mindspore.nn import Cell
  5 from mindspore import ops
  6 from mindspore import dtype as mstype
  7
  8 context.set_context(mode=context.GRAPH_MODE)
  9 context.set_context(save_graphs=True)
 10
 11 class Net(nn.Cell):
 12     def __init__(self):
 13         super().__init__()
 14         self.add = ops.Add()
 15         self.sub = ops.Sub()
 16         self.mul = ops.Mul()
 17         self.div = ops.Div()
 18
 19     def func(x, y):
 20         return self.div(x, y)
 21
 22     def construct(self, x, y):
 23         a = self.sub(x, 1)
 24         b = self.add(a, y)
 25         c = self.mul(b, self.func(a, a, b))
 26         return c
 27
 28 input1 = Tensor(3, mstype.float32)
 29 input2 = Tensor(2, mstype.float32)
 30 net = Net()
 31 out = net(input1, input2)
 32 print(out)

An error happens.

  1 [EXCEPTION] ANALYZER(31946,7f6f03941740,python):2021-09-18-15:10:49.094.863 [mindspore/ccsrc/pipeline/jit/static_analysis/stack_frame.cc:85] DoJump] The parameters number of the function is 2, but the number of provided arguments is 3.
  2 FunctionGraph ID : func.18
  3 NodeInfo: In file test.py(19)
  4     def func(x, y):
  5
  6 Traceback (most recent call last):
  7   File "test.py", line 31, in <module>
  8     out = net(input1, input2)
  9   File "/home/workspace/mindspore/mindspore/nn/cell.py", line 404, in __call__
 10     out = self.compile_and_run(*inputs)
 11   File "/home/workspace/mindspore/mindspore/nn/cell.py", line 682, in compile_and_run
 12     self.compile(*inputs)
 13   File "/home/workspace/mindspore/mindspore/nn/cell.py", line 669, in compile
 14     _cell_graph_executor.compile(self, *inputs, phase=self.phase, auto_parallel_mode=self._auto_parallel_mode)
 15   File "/home/workspace/mindspore/mindspore/common/api.py", line 542, in compile
 16     result = self._graph_executor.compile(obj, args_list, phase, use_vm, self.queue_name)
 17 TypeError: mindspore/ccsrc/pipeline/jit/static_analysis/stack_frame.cc:85 DoJump] The parameters number of the function is 2, but the number of provided arguments is 3.
 18 FunctionGraph ID : func.18
 19 NodeInfo: In file test.py(19)
 20     def func(x, y):
 21
 22 The function call stack (See file '/home/workspace/mindspore/rank_0/om/analyze_fail.dat' for more details):
 23 # 0 In file test.py(26)
 24         return c
 25         ^
 26 # 1 In file test.py(25)
 27         c = self.mul(b, self.func(a, a, b))
 28                         ^

Above exception is ‘TypeError: mindspore/ccsrc/pipeline/jit/static_analysis/stack_frame.cc:85 DoJump] The parameters number of the function is 2, but the number of provided arguments is 3…’. And it tells us FunctionGraph ID : func.18 only needs two parameters, but actually gives 3. We can find the related code is self.func(a, a, b) from ‘The function call stack … In file test.py(25)’. Easily, by checking the code, we know that we gave too much parameter to the calling function.

Sometimes the exception information is not enough easy to understand. Or we want to see the part of graph information that have evaluated. Then we can open /home/workspace/mindspore/rank_0/om/analyze_fail.dat that indicated in the exception text by using a text editing software (for example, vi).

  1 # [No.1] construct_wrapper.0
  2 # In file test.py(22)/    def construct(self, x, y):/
  3 funcgraph fg_0(
  4         %para1 : Tensor(F32)[]    # x
  5         , %para2 : Tensor(F32)[]    # y
  6     ) {
  7
  8 #------------------------> 0
  9     %1 = FuncGraph::fg_3(%para1, %para2)    #(Tensor(F32)[], Tensor(F32)[])    # fg_3=construct.3 #scope: Default
 10       # In file test.py(26)/        return c/#[CNode]2
 11     Primitive::Return{prim_type=1}(%1)    #(Undefined) #scope: Default
 12       # In file test.py(26)/        return c/#[CNode]1
 13 }
 14 # order:
 15 #   1: construct_wrapper.0:[CNode]2{[0]: ValueNode<FuncGraph> construct.3, [1]: x, [2]: y}
 16 #   2: construct_wrapper.0:[CNode]1{[0]: ValueNode<Primitive> Return, [1]: [CNode]2}
 17
 18
 19 # [No.2] construct.3
 20 # In file test.py(22)/    def construct(self, x, y):/
 21 funcgraph fg_3(
 22         %para3 : Tensor(F32)[]    # x
 23         , %para4 : Tensor(F32)[]    # y
 24     ) {
 25     %1 : Tensor(F32)[] = DoSignaturePrimitive::S-Prim-Sub{prim_type=1}[input_names=["x", "y"], output_names=["output"]](%para3, I64(1))    #(Tensor(F32)[], I64) #scope: Default
 26       # In file test.py(23)/        a = self.sub(x, 1)/#a
 27     %2 : Tensor(F32)[] = DoSignaturePrimitive::S-Prim-Add{prim_type=1}[input_names=["x", "y"], output_names=["output"]](%1, %para4)    #(Tensor(F32)[], Tensor(F32)[]) #scope: Default
 28       # In file test.py(24)/        b = self.add(a, y)/#b
 29
 30 #------------------------> 1
 31     %3 = FuncGraph::fg_18(%1, %1, %2)    #(Tensor(F32)[], Tensor(F32)[], Tensor(F32)[])    # fg_18=func.18 #scope: Default
 32       # In file test.py(25)/        c = self.mul(b, self.func(a, a, b))/#[CNode]5
 33     %4 = DoSignaturePrimitive::S-Prim-Mul{prim_type=1}[input_names=["x", "y"], output_names=["output"]](%2, %3)    #(Tensor(F32)[], Undefined) #scope: Default
 34       # In file test.py(25)/        c = self.mul(b, self.func(a, a, b))/#c
 35     Primitive::Return{prim_type=1}(%4)    #(Undefined) #scope: Default
 36       # In file test.py(26)/        return c/#[CNode]4
 37 }
 38 # order:
 39 #   1: construct.3:a{[0]: a, [1]: ValueNode<Int64Imm> 1, [2]: ValueNode<Float> Float32}
 40 #   2: construct.3:a{[0]: ValueNode<DoSignaturePrimitive> S-Prim-Sub, [1]: x, [2]: ValueNode<Int64Imm> 1}
 41 #   3: construct.3:b{[0]: ValueNode<DoSignaturePrimitive> S-Prim-Add, [1]: a, [2]: y}
 42 #   4: construct.3:[CNode]5{[0]: ValueNode<FuncGraph> func.18, [1]: a, [2]: a, [3]: b}
 43 #   5: construct.3:c{[0]: ValueNode<DoSignaturePrimitive> S-Prim-Mul, [1]: b, [2]: [CNode]5}
 44 #   6: construct.3:[CNode]4{[0]: ValueNode<Primitive> Return, [1]: c}
 45
 46
 47 #===============================================================================
 48 # num of function graphs in stack: 2

The file analyze_fail.dat has the same information format with the file .dat. The only difference is analyze_fail.dat will locate the node which inferring failed. Searching the point by the text of ------------------------>, we reach the last position of the ------------------------> 1 at line 30. The node at line 31 to 32 have an error. Its IR expression is %3 = FuncGraph::fg_18(%1, %1, %2) .... We can know the node have 3 parameters from (%1, %1, %2). But actually the function only need 2. So the compiler will fail when evaluating the node. To solve th problem, we should decrease the parameter number.