will NGX_AGAIN kill performance?

[agentzh]

On Sat, Sep 24, 2011 at 10:47 PM, Abioy Sun <abioy.sun at gmail.com> wrote:
> hi,
>
> i currently dev a module which makes multi subrequest sequently in the
> access phase handler, via returning NGX_AGAIN.
>
> my question is, will this kill the performance? and how far could it go in
> killing performance.

NGX_AGAIN is usually for non-blocking I/O operations, it's key for
good performance under high concurrency levels.

Regards,
-agentzh