PCD Trace

Program Counter Discontinuity (PCD) Trace

PCD Trace

Program Counter Discontinuity (PCD) Trace captures the PC discontinuities & simulator events during the application simulation.

PCD Trace Features

• PCD Trace records for branch/callp/ret instructions.
• PCD supports collection of simulator events - mainly memory architecture statistics.
  • To find the list of simulator events supported, open CCS - click profile - click setup & go to custom tab. Top range window will give the list of supported events.
  • Sample events name

cycle.Total
cycle.CPU
CPU.stall.mem.L1P
CPU.stall.mem.L1D
L1D.hit.summary
L1D.miss.summary
L1P.hit
L1P.miss
L2.cache.miss.summary
L2.cache.hit.summary

Supported Configuration

• Supported on all C64x+ based single-core devices.
• C6416 Cycle Accurate Simulator
• C6416 Functional Simulator

Enable PCD Trace

PCD Trace is enabled through simulator configuration to start collection. Trace collection can be halt & resume collection during simulation through GEL commands.

Configuration File Changes

Follow the steps to enable PCD trace in simulator configuration file.

• Step 1: Open CCSetup and select the simulator.
• Step 2: Identify the simulator configuration file of the selected simulator. Check the right pane of CCSetup or click the modify properties to show the configuration file path.
• Step 3: Open the simulator configuration file & search for DSP keyword. Next to DSP key is the module name of the CPU. (Ex: DSP C64xplus;)
• Step 4: Search for END <Module name> and add the module profile given below above that line. (Ex: END C64xplus;)

MODULE PROFILE;
    CALL_GRAPH ON;
    BRANCH_TRACE_EVENTS  CPU.NOP,CPU.execute_packet; // <EVENT_1>,<EVENT_2>...<EVENT_n>;
END PROFILE;

Dyanmic Start/Stop

PCD Trace can be halted & resumed collection during simulation. This support is enabled via GEL command.

• Resume Trace collection - GEL_DriverString("START_PCDT")
• Halt Trace collection - GEL_DriverString("STOP_PCDT")

PCD Trace Format

PCD Trace contains.

• Source PC - PC at which the branch/callp/ret instruction.
• Destination PC - The branch target PC.
• Memory architecture statistics - Cumulative count (w.r.t last PCD) for every configured-list of memory architecture statistics.

########################################################
SOURCE_PC|DEST_PC|RPT_COUNT|CPU.NOP|CPU.execute_packet|
########################################################
0xe0001464|0xe0001750|1|8|12|
0xe0001764|0xe00063a0|1|7|5|
0xe00063e4|0xe00010a0|1|5|10|
0xe0001154|0xe00068e0|1|14|135|
0xe00068e0|0xe0004440|1|3|3|
0xe0004448|0xe0004c00|1|5|5|

PCD Trace Usefullness

The PCD Trace can used to generate following information.

• Call Graph - The PCD can be correlated to the object file and a complete function call graph can be constructed using PCD Trace.
• Function level profiling - PCD occurring at the function boundaries can be used to visualize the function-levelprofiling data.