[erlang-questions] Linux O_DIRECT flag

Valentin Micic valentin@REDACTED
Fri Mar 14 20:45:52 CET 2008


Dear all,

One thing that has to make a top 10 most-likely-to-frustrate-you features in
LINUX is its uncontrollable usage of memory for I/O caching. Whilst good for
most applications, it seems quite redundant if you connect a big storage
array that has a cache on its own.
After a brief investigation regarding ones ability to bypass the cache
(performed by our hardware supplier), I've been told that an application may
bypass the cache by porviding additional flag to "open" system call --
O_DIRECT to be more specific. I assume that file:open/2 does not support
this flag, so I'd like to ask, before we start hacking around:  is there an
easy way to expose this flag, and would you consider it for inclusion in one
of the next releases. Provided that O_DIRECT does what we think it does, of
course.

Thanks in advance,

Valenitn.




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