标签：processes barrier threshold uvm phase b1

UVM提供uvm_barrier对多个组件进行同步协调，同时为了解决组件独立运作的封闭性需要，定义了新的类uvm_barrier_pool来全局管理uvm_barrier对象。

 uvm_barrier 可以设置一定的等待阈值，仅在有不少于该阈值的进程在等待该对象时才会触发该事件，同时激活所有正在等待的进程，使其基础进行。 

virtual function void reset (bit wakeup = 1)

       Resets the barrier.  This sets the waiter count back to zero.

       The threshold is unchanged.  After reset, the barrier will force processes to wait for the threshold again.

       If the wakeup bit is set, any currently waiting processes will be activated.

virtual function void set_auto_reset (bit value = 1)

      The default is on, so when a barrier hits its threshold it will reset, and new processes will block until the threshold is reached again.

      If auto reset is off, then once the threshold is achieved, new processes pass through without being blocked until the barrier is reset.

virtual function void set_threshold (int  threshold)

This determines how many processes must be waiting on the barrier before the processes may proceed.

Once the threshold is reached, all waiting processes are activated.

If threshold is set to a value less than the number of currently waiting processes, then the barrier is reset and waiting processes are activated.

 1 //----------------------------------------------------------------------
 2 //component1
 3 //----------------------------------------------------------------------
 4  
 5 class comp1 extends uvm_component;
 6   uvm_barrier b1;
 7   ...
 8   function void build_phase(uvm_phase phase);
 9     super.build_phase(phase);
10     b1 = uvm_barrier_pool::get_global("b1");
11   endfunction
12   task run_phase(phase);
13     #5ns;
14     b1.wait_for();
15   endtask
16 endclass
17  
18 //----------------------------------------------------------------------
19 //component2
20 //----------------------------------------------------------------------
21  
22 class comp2 extends uvm_component;
23   uvm_barrier b1;
24   ...
25   function void build_phase(uvm_phase phase);
26     super.build_phase(phase);
27     b1 = uvm_barrier_pool::get_global("b1");
28   endfunction
29   task run_phase(phase);
30     #10ns;
31     b1.wait_for();
32   endtask
33 endclass
34 //----------------------------------------------------------------------
35 //env
36 //----------------------------------------------------------------------
37  
38 class env extends uvm_env;
39   comp1 c1;
40   comp2 c2;
41   uvm_barrier b1;
42   ...
43   function void build_phase(uvm_phase phase);
44     super.build_phase(phase);
45     c1 = comp1::type_id::create("c1",this);
46     c2 = comp1::type_id::create("c2",this);
47     b1 = uvm_barrier_pool::get_global("b1");
48   endfunction
49  
50   task run_phase(phase);
51     b1.set_threshold(3);
52     #20ns;
53     b1.set_threshold(2);
54     `uvm_info("BAR",$sformatf("set b1 thrd %0d at %0t fs",b1.get_threshold(),$time),UVM_NONE)
55   endtask
56 endclass

为了同步c1和c2而定义了b1,b1为c1,c2和env共享。c1和c2通过wait_for()来等待激活，env通过设置阈值来调控“开闸”的时间。

————————————————
版权声明：本文为CSDN博主「lbt_dvshare」的原创文章，遵循CC 4.0 by-sa版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/lbt_dvshare/article/details/82713831

标签：processes,barrier,threshold,uvm,phase,b1
来源： https://www.cnblogs.com/camellia3371----/p/11389197.html

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。