On Wed, May 20, 2009 at 08:00:47AM +0200, sebastien dugue wrote: > > Well not really, because if we stay below MMAP_THRESHOLD, as we do > with 4K pages, the only overhead is malloc's chaining structure. The > extra space used to align the buffer is released before posix_memalign() > returns, but that does increase fragmentation of mallocs chunks. > > Also, for 4K pages, mmap() systematically results in a syscall whereas > posix_memalign() does not necessarily, but as we're not on a fast path > I'm not sure what would be best. I don't mind converting all QP buffers > allocation to mmap(), but I'd like to hear what people think. >
If the only reasoning behind using a MMAP_THRESHOLD is to avoid the system call for smaller allocations, then I think we'd better use a uniform allocation scheme -- mmap -- as you proposed and not distinguish between the two cases. _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
