Re: [exim-dev] Old topic again: Option to avoid fsync()?

On Thu, 11 Jan 2007, Philip Hazel wrote:

> It is clear that this is a controversial issue. Perhaps the resolution
> is to add the option, but require a compile time configuration to
> include the feature. Then it would certainly have zero impact on anybody
> who chose not to include it in the binary. If you have it in the binary
> but do not turn it on, the impact is a flag test every time Exim might
> do an fsync(). I suspect this is a very small cost compared with
> everything else that's going on.

OK, I've tried to make everyone happy. I have added a compile-time
option called ENABLE_DISABLE_FSYNC, and put a lot of warnings about it
in EDITME. In particular, I've said it should never be used when
compiling binaries for distribution.

If ENABLE_DISABLE_FSYNC is set, a runtime option called disable_fsync is
compiled. If the compile time option is not set, an attempt to use the
runtime option gets "unknown option".

This code is committed to CVS and so will be in tonight's snapshot.

Philip

--
Philip Hazel, University of Cambridge Computing Service.