Messages in this thread | | | Date | Sun, 13 May 2007 19:53:41 -0400 | From | Jeff Garzik <> | Subject | Re: [PATCH] "volatile considered harmful" document |
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On Sun, May 13, 2007 at 07:26:13PM -0400, Bill Davidsen wrote: > Krzysztof Halasa wrote: > >Robert Hancock <hancockr@shaw.ca> writes: > >>You don't need volatile in that case, rmb() can be used.
> >rmb() invalidates all compiler assumptions, it can be much slower.
It does not invalidate /all/ assumptions.
> Yes, why would you use rmb() when a read of a volatile generates optimal > code?
Read of a volatile is guaranteed to generate the least optimal code. That's what volatile does, guarantee no optimization of that particular access.
Jeff
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