Greg Freemyer wrote:
> On 3/8/07, Tzahi Fadida <Tzahi.ML2@xxxxxxxxx> wrote:
>> On Thursday 08 March 2007 10:30, Anupam Kapoor wrote:
>> >
>> > don't use volatile in the kernel. straight from horse's mouth :
>>
>> I don't understand, LDD3 uses volatile in drivers. Now they say i can't.
>> What is the alternative?
>>
> Interesting, that thread is recommending "optimization barriers". I
> wasn't familiar with those.
>
> syntax example:
>> for (int i=0; i<10; i++)
>> {
>> a[i] = *ina;
>> barrier();
>> b[i] = *inb;
>> }
>
> And the description is:
>> It's a full optimization barrier; the compiler assumes all
>> register and memory content has changed from before the barrier(), and
>> it will start "fresh".
Which is *much* more pessimistic than "volatile".
~chill
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