On Fri, 2005-07-22 at 00:37 +0200, J. Mayer wrote: > We agreed with Fabrice that there should be at least one more > indirection in page mapping, because it would cost too much memory to > try to map the whole needed memory space in one table, even if we can > "forget" some of the middle bits in most cases.
I haven't had time to even look at the qemu code, but in my last emulator, we found it was fastest to keep a sorted array of chunks of memory instead of some sort of tree. To fetch a chunk of memory, you would scan through the device list for a chunk that covered that range and swap it with the previous chunk in the list. System RAM bubbled to the top and the control structures of a particular timer that our real code used bubbled to the top. Most access is to system RAM, so there is only one indirection most of the time. We had a 15% speed improvement over using a hash table. (disclaimer, we were implementing in Java, so array access is a bit slow due to bounds checking.) Knuth has a name for the data structure, but I don't remember what it is. -- Joe Batt <[EMAIL PROTECTED]> _______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
