的/ proc / SYS / FS / AIO-NR从不大于1024（AIO在Linux上） [英] /proc/sys/fs/aio-nr is never higher than 1024 (AIO on linux)

问题描述

我试图在Linux上使用异步IO。据我所知，是3个选项：

I'm trying to use async io on linux. As far as i know there're 3 options:

• 内核调用（io_submit和朋友）


• libRT - 使用线程在用户空间


• libRTKAIO - 内核调用的包装不使用线程

我使用的是最后的选择，而我看到，一个运行在很多多线程异步IO请求，在我的单元测试，的/ proc / SYS / FS / AIO-NR永远不会比1024我不知道高在这里奠定了这样的限制。

I'm using the last option, and i see, that in my unit test that runs a lot of async io requests in multiple threads, /proc/sys/fs/aio-nr is never higher than 1024. I wonder where lays such limitation.

我给自己定的/ proc / SYS / FS / AIO-MAX-NR 16M的，所以它不是一个问题。

I've set /proc/sys/fs/aio-max-nr to 16M, so it's not an issue.

一个相关的问题（也是我）<一个href=\"http://stackoverflow.com/questions/1763712/aiowrite-on-linux-with-rtkaio-is-sometimes-long\">http://stackoverflow.com/questions/1763712/aiowrite-on-linux-with-rtkaio-is-sometimes-long

A related question (also mine) http://stackoverflow.com/questions/1763712/aiowrite-on-linux-with-rtkaio-is-sometimes-long

推荐答案

有一个名为io_setup一个系统调用。在librtkaio此调用接收1024作为参数。这一点，因为我描述的，如果有是平行超过1024 IOS伤害的表现引出恒1024
需要注意的是1024是很难codeD。

There's a system call named "io_setup". In librtkaio this call is receiving 1024 as an argument. This, leads to the constant 1024 as i described and hurts performance if there're more than 1024 ios in parallel. Note that 1024 is hardcoded.

只有lio_listio会将呼叫阻塞模式将允许你提出的1024个吧。

Only calling lio_listio in blocking mode will allow you to raise this 1024 bar.

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