2012

我的饭 [1]

哇嘞，离上一篇 我的饭 [0] 距离2年多…

Lion经验两则

最近经历的Lion下比较想记一笔的经验，凑个数吧。

安装gevent，Lion上

不出所料，凡是带本地绑定的Python库，在Mac上多多少少都别扭一些。 今天是pip install gevent的时候出错：

抢回域名

好久没写点什么了，今天也只是为了纪念一件事情：抢回丢了5年的域名，iusr.net。

Biased Locking && Bulk Rebiasing

也是老东西了…以前没有整理记录的习惯，哎。

1. Early research utilized property that mostsynchronization in Java language is uncontended.
   • not only uncontended,but unshared
   • Most objects locked / unlocked by exactly one thread inthe object’s lifetime
2. Avoid creation of mutex/condvar per Java object. ——不是完全免费的
3. Compare-and-swap / compare and exchange
4. “Inflate” to full heavyweight monitor if contention detected
5. Previous:
   • First thread locking the object reserves the lock with an atomic operation
     • Subsequent locks / unlocks by that thread use no atomic operations
     • Recursion count in object header detects IllegalMonitorStateException
     • Using non-atomic stores
   • If another thread locks the object, relativelyexpensive unreservation required
     • Involves sending signal to reservation owner thread
     • Ensures reservation owner thread not performing concurrent non-atomic stores
6. New
   • Store-Free Biased Locking
   • Bulk rebiasing and bulk revocation
   • Epoch-based bulk rebiasing

有关并发

最近那个靠谱的小朋友开始看OpenJDK 6的源代码，相比之下真是让我汗颜，我机器里的代码都扔在那儿很久了。