mongodb - Linux Transparent Huge Pages (THP)性能评估

Question

您能告诉我一些真实的应用示例，这些示例显示了 Linux 的透明大页面 (THP) 导致的性能下降吗？一些主页上说数据库应用程序(Hadoop、mongoDB、redis 等)表现出性能下降，但我无法确认结果。

我想评估使用 THP 或不使用 THP 的性能。谢谢。

Answer 1

对于 redis，性能下降已得到充分记录和测试，建议禁用大页面，来自 redis 的 TFM:

Unfortunately when a Linux kernel has transparent huge pages enabled, Redis incurs to a big latency penalty after the fork call is used in order to persist on disk. Huge pages are the cause of the following issue: Fork is called, two processes with shared huge pages are created. In a busy instance, a few event loops runs will cause commands to target a few thousand of pages, causing the copy on write of almost the whole process memory. This will result in big latency and big memory usage.

参见:

http://antirez.com/news/84

http://redis.io/topics/latency