UVM Tutorial for Candy Lovers – 28. Message Logging

In the previous article, we explained how to filter messages using a verbosity threshold. This article explains how to send the messages to a file (or files).

Message Example

As an example, we added several message macros with different severity to the functional coverage subscriber.

class jelly_bean_fc_subscriber extends uvm_subscriber#( jelly_bean_transaction );
  // ...
  function void write( jelly_bean_transaction t );
    jb_tx = t;
    jelly_bean_cg.sample();
 
    //_SEVERITY_  _ID__  ___________________MESSAGE____________________
    `uvm_info   ( "id1", { t.color.name(), " ", t.flavor.name(), " 1" }, UVM_NONE )
    `uvm_info   ( "id2", { t.color.name(), " ", t.flavor.name(), " 2" }, UVM_NONE )
    `uvm_warning( "id1", { t.color.name(), " ", t.flavor.name(), " 3" } )
    `uvm_warning( "id2", { t.color.name(), " ", t.flavor.name(), " 4" } )
    `uvm_error  ( "id1", { t.color.name(), " ", t.flavor.name(), " 5" } )
    `uvm_error  ( "id2", { t.color.name(), " ", t.flavor.name(), " 6" } )
    `uvm_fatal  ( "id1", { t.color.name(), " ", t.flavor.name(), " 7" } )
    `uvm_fatal  ( "id2", { t.color.name(), " ", t.flavor.name(), " 8" } )
  endfunction: write
endclass: jelly_bean_fc_subscriber

The following figure summarizes the messages defined in the subscriber.

Messages Defined in the Subscriber

Preparation

Opening File Descriptors

In this article, we will write to four files (default_file, warning_file, id1_file, and warning_id1_file). We open the file descriptors in the start_of_simulation_phase (lines 8 to 11).

class jelly_bean_test extends uvm_test;
  protected int default_fd; // file descriptor
  protected int warning_fd;
  protected int id1_fd;
  protected int warning_id1_fd;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    default_fd     = $fopen( "default_file",     "w" );
    warning_fd     = $fopen( "warning_file",     "w" );
    id1_fd         = $fopen( "id1_file",         "w" );
    warning_id1_fd = $fopen( "warning_id1_file", "w" );
    // ...
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

Setting Reporting Actions

By default, no message is sent to the files because the default actions are defined as follows:

Severity	Default Actions	Description
UVM_INFO	UVM_DISPLAY	Sends the message to the standard out
UVM_WARNING	UVM_DISPLAY	Sends the message to the standard out
UVM_ERROR	UVM_DISPLAY | UVM_COUNT	Sends the message to the standard out; Terminates the simulation if the number of messages exceeds the number specified by the +UVM_MAX_QUIT_COUNT (default is 0)
UVM_FATAL	UVM_DISPLAY | UVM_EXIT	Sends the message to the standard out; Terminates the simulation immediately

set_report_severity_action

In order to send the messages to a file, we need to add the UVM_LOG action to each severity using the set_report_severity_action function (lines 5 to 8).

class jelly_bean_test extends uvm_test;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    // ...                                   _SEVERITY__  _______ACTIONS_______
    jb_env.jb_fc.set_report_severity_action( UVM_INFO,    UVM_DISPLAY | UVM_LOG );
    jb_env.jb_fc.set_report_severity_action( UVM_WARNING, UVM_DISPLAY | UVM_LOG );
    jb_env.jb_fc.set_report_severity_action( UVM_ERROR,   UVM_DISPLAY | UVM_LOG );
    jb_env.jb_fc.set_report_severity_action( UVM_FATAL,   UVM_DISPLAY | UVM_LOG );
    // ...
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

We removed the UVM_COUNT and UVM_EXIT actions from the UVM_ERROR and UVM_FATAL so that a simulation continues even after hitting an error. You should probably keep them in a real test-bench, though.

You can set ID-specific action using set_report_id_action, and severity-and-ID-specific action using set_report_severity_id_action, too. See the UVM manual for the detail.

Sending Messages to a File

set_report_default_file

If you just want to direct the messages to a file, you can use the set_report_default_file function. The following code sends the messages issued by the functional coverage subscriber to the default_file (line 5).

class jelly_bean_test extends uvm_test;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    // ...                                FILE_DESCRIPTOR
    jb_env.jb_fc.set_report_default_file( default_fd );
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

Sending Messages to a Default File

When you run a simulation, the default_file will store the messages like this:

UVM_INFO /home/runner/env.svh(40) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 1
UVM_INFO /home/runner/env.svh(41) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 2
UVM_WARNING /home/runner/env.svh(42) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 3
UVM_WARNING /home/runner/env.svh(43) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 4
UVM_ERROR /home/runner/env.svh(44) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 5
UVM_ERROR /home/runner/env.svh(45) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 6
UVM_FATAL /home/runner/env.svh(46) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 7
UVM_FATAL /home/runner/env.svh(47) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 8

Setting Severity-specific File

set_report_severity_file

If you want to direct the messages with a specific severity to a separate file, you can do so using the set_report_severity_file function. For example, you can store the messages with UVM_WARNING severity to the warning_file as follows (line 5):

class jelly_bean_test extends uvm_test;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    // ...                                 _SEVERITY__  FILE_DESCRIPTOR
    jb_env.jb_fc.set_report_severity_file( UVM_WARNING, warning_fd );
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

Note that in our example, we still set the default file as we did in the previous section. Severity-specific file takes precedence over the default file.

Directing Severity-specific Messages

When you run a simulation, the default_file will store the messages like this:

UVM_INFO /home/runner/env.svh(40) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 1
UVM_INFO /home/runner/env.svh(41) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 2
UVM_ERROR /home/runner/env.svh(44) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 5
UVM_ERROR /home/runner/env.svh(45) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 6
UVM_FATAL /home/runner/env.svh(46) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 7
UVM_FATAL /home/runner/env.svh(47) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 8

The warning_file will store the messages like this:

UVM_WARNING /home/runner/env.svh(42) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 3
UVM_WARNING /home/runner/env.svh(43) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 4

Setting ID-specific File

set_report_id_file

If you want to direct the messages with a specific ID to a separate file, you can do so using the set_report_id_file function. For example, you can store the messages with "id1" to the id1_file as follows (line 5):

class jelly_bean_test extends uvm_test;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    // ...                           _ID__  FILE_DESCRIPTOR
    jb_env.jb_fc.set_report_id_file( "id1", id1_fd );
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

Note that in our example, we still set the default file and severity-specific file as we did in the previous sections. ID-specific file takes precedence over the severity-specific file (and default file).

 

                                                                  Directing ID-specific Messages

When you run a simulation, the default_file will store the messages like this:

UVM_INFO /home/runner/env.svh(41) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 2
UVM_ERROR /home/runner/env.svh(45) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 6
UVM_FATAL /home/runner/env.svh(47) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 8

The warning_file will store the messages like this:

UVM_WARNING /home/runner/env.svh(43) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 4

The id1_file will store the messages like this:

UVM_INFO /home/runner/env.svh(40) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 1
UVM_WARNING /home/runner/env.svh(42) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 3
UVM_ERROR /home/runner/env.svh(44) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 5
UVM_FATAL /home/runner/env.svh(46) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 7

Setting Severity-and-ID-specific File

set_report_severity_id_file

If you really want to direct the messages with a specific severity and a specific ID to a separate file, you can do so using the set_report_severity_id_file function. For example, you can store the messages with UVM_WARNING severity and "id1" to the warning_id1_file as follows (line 5):

class jelly_bean_test extends uvm_test;
  // ...
  function void start_of_simulation_phase( uvm_phase phase );
    // ...                                    _SEVERITY__  _ID__  FILE_DESCRIPTOR
    jb_env.jb_fc.set_report_severity_id_file( UVM_WARNING, "id1", warning_id1_fd );
  endfunction: start_of_simulation_phase
endclass: jelly_bean_test

Note that in our example, we still set the default file, severity-specific file, and ID-specific file as we did in the previous sections. Severity-and-ID-specific file takes the highest precedence.

                                                                     Directing Severity-and-ID-specific Messages

When you run a simulation, the default_file will store the messages like this:

UVM_INFO /home/runner/env.svh(41) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 2
UVM_ERROR /home/runner/env.svh(45) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 6
UVM_FATAL /home/runner/env.svh(47) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 8

The warning_file will store the messages like this:

UVM_WARNING /home/runner/env.svh(43) @ 25: uvm_test_top.jb_env.jb_fc [id2] GREEN BUBBLE_GUM 4

The id1_file will store the messages like this:

UVM_INFO /home/runner/env.svh(40) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 1
UVM_ERROR /home/runner/env.svh(44) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 5
UVM_FATAL /home/runner/env.svh(46) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 7

Finally, the warning_id1_file will store the messages like this:

UVM_WARNING /home/runner/env.svh(42) @ 25: uvm_test_top.jb_env.jb_fc [id1] GREEN BUBBLE_GUM 3