Data Snapshots - 2025.2 English - UG1076

The x86simulator --dump data snapshot feature allows you to dump and inspect data traffic at kernel ports without using the debugger. Using data snapshots does not require any instrumentation of kernel code. Data snapshots also helps diagnose simulation result mismatches between two versions of the same design with x86simulator. Kernel ports including streams, windows, packet streams, cascade streams, and RTP ports all support data snapshots. All platform level ports such as PLIO, GMIO, RTP ports, and PS accesses into a specific RTP port also support this feature.

For input window ports, each time the kernel acquires the window a data snapshot is taken. The snapshot includes the margin. For output window ports, a snapshot is taken each time the kernel releases the window. The snapshot excludes the margin.

In both cases, the snapshot consists of the kernel iteration count and sample data. The snapshot feature generates one text file per kernel port and records the iteration count of the kernel. Following is an example of a data snapshot for a graph with a chain of two kernels with window ports. The first window has a non-zero margin.

$x86simulator --pkg-dir=./Work --i=.. --dump
INFO: Reading options file './Work/options/x86sim.options'.
Processing './x86simulator_output/dump/x86sim_dump.data'
File Port direction Port type Data type Kernel or platform port
------------------------ -------------- --------- ---------
-----------------------
platform_src_0.txt out window cint16 platform.src[0]
mygraph_first_in_0.txt in window cint16 mygraph.first.in[0]
mygraph_second_out_0.txt out window cint16 mygraph.second.out[0]
platform_sink_0.txt in window cint16 platform.sink[0]
mygraph_first_out_0.txt out window cint16 mygraph.first.out[0]
mygraph_second_in_0.txt in window cint16 mygraph.second.in[0]
Wrote './x86simulator_output/dump/platform_src_0.txt'
Wrote './x86simulator_output/dump/mygraph_first_in_0.txt'
Wrote './x86simulator_output/dump/mygraph_second_out_0.txt'
Wrote './x86simulator_output/dump/platform_sink_0.txt'
Wrote './x86simulator_output/dump/mygraph_first_out_0.txt'
Wrote './x86simulator_output/dump/mygraph_second_in_0.txt'
Simulation completed successfully returning zero
$> more ./x86simulator_output/dump/mygraph_first_in_0.txt
# port: mygraph.first.in[0]
# port_dir: in
# port_type: window
# data_type: cint16
# Iteration 1; snapshot 1
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 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
# Iteration 2; snapshot 2
48 49
50 51
52 53
54 55
56 57
58 59
60 61
62 63
1 0
3 2
5 4
7 6
9 8
11 10
13 12
15 14
17 16
19 18
21 20
23 22
25 24
27 26
29 28
31 30
33 32
35 34
37 36
39 38
41 40
43 42
45 44
47 46
49 48
51 50
53 52
55 54
57 56
59 58
61 60
63 62

For stream ports, the system takes a data snapshot for each chunk of four bytes of data. Each snapshot includes the value of TLAST and the kernel iteration count. For cascade stream ports, the granularity is eight bytes.

For example, a data snapshot for a graph with three kernels connected via stream ports is as follows.

$ x86simulator --pkg-dir=./Work --i=.. --dump
INFO: Reading options file './Work/options/x86sim.options'.
Processing './x86simulator_output/dump/x86sim_dump.data'


File Port direction Port type Data type Kernel or platform port
-------------------------- -------------- --------- --------- -----------------------
platform_src_0.txt out stream int32 platform.src[0] 
fifo_graph_dist_in_0.txt in stream int32 fifo_graph.dist.in[0] 
fifo_graph_aggr_out_0.txt out stream int32 fifo_graph.aggr.out[0] 
platform_sink_0.txt in stream int32 platform.sink[0] 
fifo_graph_comp0_in_0.txt in stream int32 fifo_graph.comp0.in[0] 
fifo_graph_comp1_in_0.txt in stream int32 fifo_graph.comp1.in[0] 
fifo_graph_dist_out_0.txt out stream int32 fifo_graph.dist.out[0] 
fifo_graph_comp0_out_0.txt out stream int32 fifo_graph.comp0.out[0]
fifo_graph_aggr_in_0.txt in stream int32 fifo_graph.aggr.in[0] 
fifo_graph_comp1_out_0.txt out stream int32 fifo_graph.comp1.out[0]
fifo_graph_aggr_in_1.txt in stream int32 fifo_graph.aggr.in[1] 


Wrote './x86simulator_output/dump/platform_src_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_dist_in_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_aggr_out_0.txt'
Wrote './x86simulator_output/dump/platform_sink_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_comp0_in_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_comp1_in_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_dist_out_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_comp0_out_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_aggr_in_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_comp1_out_0.txt'
Wrote './x86simulator_output/dump/fifo_graph_aggr_in_1.txt'
Simulation completed successfully returning zero


$ more ./x86simulator_output/dump/fifo_graph_dist_in_0.txt
# port: fifo_graph.dist.in[0]
# port_dir: in
# port_type: stream
# data_type: int32
# Iteration 1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
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...

The compiler generates the configuration file ./Work/options/x86sim_dump.config which specifies the data to dump when running x86simulator --dump. Following is an example of compiler-generated ./Work/options/x86sim_dump.config:

kernel=yes
gr.k[0].in[0]=yes
gr.k[0].out[0]=yes
gr.k[0].out[1]=yes
gr.k[1].in[0]=yes
gr.k[1].in[1]=yes
gr.k[1].out[0]=yes

platform_io=no
gr.in.out[0]=no
gr.dataout.in[0]=no

The configuration file supports the following categories based on the design.

Setting the dump configuration to yes, dumps all entries under the category, irrespective of their control value.

If you set the dump configuration to no, partial entries under the category can be selected to be dumped. Dumping saves disk space and running time. For example, the following configurations only apply to dump gr.k[0].in[0]:

kernel=no
gr.k[0].in[0]=yes
gr.k[0].out[0]=no
gr.k[0].out[1]=no
gr.k[1].in[0]=no
gr.k[1].in[1]=no
gr.k[1].out[0]=no

If you set no dump configuration to a category, the value of the previous category is inherited. For example, the following entries g.ifm1 and g.wts1 are under the category shared_buffer. However, the dump configuration for shared_buffer is not specified. So, the value of the previous category kernel which is yes is inherited. Then, the entries g.ifm1 and g.wts1 are all dumped.

kernels=yes
g.k1.in[0]=yes
g.k1.in[1]=yes
g.k1.out[0]=yes

g.ifm1=yes
g.wts1=no