Optimize keytablelist implementation

MJY-HUST commented 2 months ago

What problem does this PR solve?

Issue Number: #2756

Problem Summary:

设置thread_local的keytable_list长度上限为KEY_TABLE_LIST_SIZE = 10000
超出KEY_TABLE_LIST_SIZE 后，返回KEY_TABLE_LIST_SIZE / 2 个 keytable给全局的free_keytables
当前thread的keytable_list为空但是free_keytables不为空时，一次性从free_keytables中取出至多BORROW_FROM_GLOBLE_SIZE = 100 个keytable给keytable_list

What is changed and the side effects?

Changed:

Side effects:

Performance effects(性能影响):
Breaking backward compatibility(向后兼容性):

Check List:

Please make sure your changes are compilable(请确保你的更改可以通过编译).
When providing us with a new feature, it is best to add related tests(如果你向我们增加一个新的功能, 请添加相关测试).
Please follow Contributor Covenant Code of Conduct.(请遵循贡献者准则).

wwbmmm commented 2 months ago

补充一些单测吧，感觉现有的单测没有覆盖到新增的代码

MJY-HUST commented 2 months ago

补充一些单测吧，感觉现有的单测没有覆盖到新增的代码

补充了两个单测：场景一：启动多个bthread，获取keytable后bthread_usleep，模拟issue中的场景场景二：启动多个bthread，一组bthread直接调用borrow_keytable获取keytable并存放到全局链表，另一组从全局链表中获取keytable并return_keytable，这些bthread理论上都不会发生切换，来模拟keytable不均衡的场景。两个场景均检查thread local list的长度小于bthread::FLAGS_key_table_list_size

MJY-HUST commented 2 months ago

缩进改成4个空格吧

已修改

wwbmmm commented 2 months ago

LGTM

chenBright commented 1 month ago

@lsdh-fei 可以验证一下这个PR能否解决#2756 的问题吗？

apache / brpc