Issue 1545275: new directio module (original) (raw)

This module is an interface to the open(),read(),write() and close() system calls on a Direct I/O context (O_DIRECT flag to the open() system call). The O_DIRECT flag allows to open a file in "direct" mode -- effectively bypassing the buffer-cache. This behaviour is generally not a good thing since it will strongly degrade performances, but it can be desirable for some purposes (benchmark, or optimized read of many concurrent video streams, for instance). A special interface is needed, since the read() system calls requires aligned buffers when used on O_DIRECT file descriptors. And since the flag O_DIRECT is not available with the os module, we decided to write this module.

We would like to know if this is worth for inclusion in the standard Python distribution? What should be modified to make it more "compliant" to the python rules? This file will probably need to be updated to conform to python style standards.

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The major problem with this module is that it is LGPL; for inclusion in the library, a contribution form to the PSF would be required and your license be changed.

In any case, it's not clear what the applicability of this specialized API is. My suggestion would be to package it up with distutils and put it on the Cheeseshop (cheeseshop.python.org). When there is an established user base, and demand that it be included in the standard distribution, inclusion should be discussed on python-dev.