Re: [boost] Help needed for shared_ptr issue on iPad2 (dualcore ARM)

Subject: Re: [boost] Help needed for shared_ptr issue on iPad2 (dualcore ARM)
From: Peter Dimov (pdimov_at_[hidden])
Date: 2011-03-28 12:58:28

Phil Endecott wrote:

> One other issue is that even when enabled, SWP might not have the required 
> memory barrier semantics on the multi-processor systems, i.e. you might 
> need to put explicit barrier instructions either side of it.

Yes, you may be right about this. It could be the lack of a memory barrier 
(DMB) that causes the spinlock to not work properly. (I'm not quite sure 
what exactly DSB and ISB can be used for - maybe one of those could be 
enough.)