fsdb那些事

$fsdbDumpfile("abc.fsdb",1000); // 后面的数字1000就表示1000M,表示限定这个fsdb最大1000M就不dump了$fsdbAutoSwitchDumpfile(200,"abc.fsdb",5); //表示dump 5个最大200M的fsdb，最后得到的应该是5个 abc***.fsdb

2.  另外的通过hierarchical存多个fsdb

$fsdbDumpvars(1,top,"+fsdbfile+abc.fsdb"); //dump top这一层到abc.fsdb这个文件里$fsdbDumpvars(0,top.cpu,"+fsdbfile+cd.fsdb") ;  //dump top.cpu全部到cd.fsdb里面

initial  begin#1000_000;$fsdbDumpvars("aa.fsdb");end

$fsdbDumpon; // - 打开 FSDB dumping$fsdbDumpoff; // - 关闭 FSDB dumping

5.  Conventional Issues & Verdi’s Approach

Issues and Conventional Approach
• Today’s complex SOC designs usually require huge amounts of data
for verification which introduces some problems when dealing with big simulation dump files.
• A common problem with complex design dumping is that the dumped simulation file may exceed the OS limitation, or the simulation
process may exceed the OS memory limitation during dumping.
• The workarounds is to limit the signal number by dumping from a specified scope in hierarchy or start dumping after a certain time.

Verdi’s Approach
• Verdi provides various environment variables and system tasks to restrict the FSDB file size in different constraints, to get the best balance between data accuracy and performance
• Verdi also provides a parallel dumping mechanism to speed up the dumping performance in dual CPU machines.

5.1 Restrict the FSDB File Size (1/4)

NOVAS_FSDB_ENV_WRITER_MEM_LIMIT variable:

• The default value is 64.

• When the user uses the nWave auto-update feature, the recommendation is to set this environment variable to a smaller value before running the simulation. For example:% 

5.2 Skip dumping VHDL complex data.

• Including array of array and record signals.

% setenv IGNORE_COMPLEX 1

5.4 Restrict the FSDB File Size (2/4)

Use $fsdbAutoSwitchDumpfileto reduce the size and control the number of FSDB files.

• For example, if the maximum desired FSDB file size is 1G and at most 20 FSDB dump files can be created, add following task in source code:

$fsdbAutoSwitchDumpfile(1000, "ALU.fsdb", 20, "my.log");

• Where 1000 (1G) is the size of each file and 20 is the number of dump files.

initial begin$fsdbDumpfile ("../log/test1.u_bar.3.fsdb");$fsdbDumpvars (3, top.u_foo.u_bar);end

$fsdbSuppress(system.i_pram, system.i_cpu.i_CCU);$fsdbDumpvars;

5.7 Use $fsdbDumpMem/$fsdbDumpMDA to dump the relevant cells of the memory/MDA at specific time intervals.
• Dump the memory cells from mem[0] to mem[31] at the time the system task is called:

$fsdbDumpMem(mem, 0, 32);

$fsdbDumpMem(mem, 0, 32, , WR_ENABLE, 23);

$fsdbDumpMem(mem, , , 500, WR_ENABLE, 20);

initial begin$fsdbDumpvars;#1000 $fsdbDumpoff;#70000 $fsdbDumpon;end

5.10 Parallel Dumping for FSDB

Two functions are includedin the process when dumping FSDB:

• Running the simulation and

• Writing the FSDB.

Use parallel dumping mechanism to separate these two process in a multi-processor system.Two ways to run simulation in parallel mode:

• Add +fsdb_parallel option in command line when runningsimulation.

• Set environment variable FSDB_PARALLEL before runningsimulation.

• setenv FSDB_PARALLEL 1

NOVAS_FSDB_ENV_DUMP_SEQ_NUM

6.fsdbDumplimit - 限制FSDB 文件size  如何使用？

7. Specify the option in an FSDB dumping command to enable dumping allsupported signals:

$fsdbDumpvars("+all");

The Novas object files for FSDB dumping provide the following FSDB dumpingcommands for Verilog:

$fsdbAutoSwitchDumpfile$fsdbDumpfile$fsdbDumpflush$fsdbDumpon, $fsdbDumpoff $fsdbDumpvars$fsdbDumpvarsByFile$fsdbDumpvarsES$fsdbDumpFinish$fsdbDumpMDA$fsdbDumpSVA$fsdbLog$fsdbReplay$fsdbSuppress$fsdbSwitchDumpfile$fsdbDumpfile

To specify the FSDB file name created by the Novas object files for FSDBdumping. If not specified, the default FSDB file name is "novas.fsdb" . This command is valid only before $fsdbDumpvars is executed and is ignored if specified after $fsdbDumpvars . 

To restrict the largest dump file size to the user-defined size limitation, pleasespecify the limit size in megabyte format. This function will affect the FSDB filethat is specified in "FSDB_Name" . The FSDB dumper uses the sliding windowscheme to keep the last signal values in the FSDB file. It drops the old values if file size exceeds the user-specified limitation.

For $fsdbDumpvars ,$fsdbDumpMDA,$fsdbDumpvarsES,$fsdbDumpSVA and $fsdbDumpvarsByFile , user can use the option "+fsdbfile+filename.fsdb" tospecify the target FSDB file to dump. It is equal to using $fsdbDumpfile then $fsdbDumpvars.

$fsdbDumpfile("FSDB_Name" | FSDB_Name_var [ ,Limit_Size |,Limit_Size_var ]);

when specified on the simulator command line:

xcelium> call fsdbDumpfile \"rtl.fsdb\"xcelium> call fsdbDumpvars 0 TB //1st argument is 'level', 2nd argument is 'scope'//the 'level' values allow different depths of the hierarchy below the named scope//0: all signals in all scopes//1: all signals in current scope//2: all signals in the current scope and all scopes one level below//n: all signals in the current scope and all scopes n-1 level below

$fsdbDumpfile("FSDB_Name");$fsdbDumpfile("FSDB_Name", Limit_Size);

8.1 命令介绍：

还可以直接指定dump的fsdb file

$fsdbDumpvars(0,top.arbiter,"+fsdbfile+novas.fsdb");

$fsdbDumpMDA(depth, instance, "options") dump指定模块中的多维数组

$fsdbDumpSVA(depth,instance,"option")，dump指定模块的assertion

$fsdbDumpSVA(1,system.arbiter,"+fsdbfile=SVA.fsdb"),将该instance下所有assert全部dump到该fsdb中  可以用+fsdbfile=SVA.fsdb dump到新的fsdb文件中.

$fsdbSwitchDumpfile(“new_file_name”[, “+fsdbfile+src_file”])

关闭现有的波形文件，以一个新的文件名开始加载波形；

new_file_name—创建一个新的波形文件，将波形加载到这个文件中；

+fsdbfile+src_file—指定要停止加载并关闭的波形文件， 这个参数不指定时，将默认使用当前正在加载的波形文件；

8.2 实际操作：

有按size切不同fsdb文件需求，可以如下操作，这里fsdbDumpvars指定了特定的module，也可以直接从top上dump所有的波形.

付费文章汇总（截止2024年06月02日）

fsdbDump用法

将fsdb波形文件dump到多个文件中

分享《verdi用法小结》的pdf

Verdi用法小结

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