On Thu, Jul 24, 2008 at 01:49:34PM +0100, Howard Wilkinson wrote: > > I am looking for a definitive answer to the question of where the PAE > kernels become useful. I have seen various articles that mention needing > PAE kernels if you have more then 4GB of physical memory in a 32-bit > processor environment. I have also seen statements that say you need > them if you have 4GB or more of memory. Now which is right? Also, even > if you need a PAE kernel because the last few bytes are not addressable > when you have exactly 4GB is this useful or is the trade off of larger > page tables and pages going to eat any benefit of being able to address > these few bytes and if so when does the PAE kernel become useful? > http://en.wikipedia.org/wiki/Physical_Address_Extension Can you be more specific and define 'useful'. In general on a 32 bit system you will have 32 bit pointers by default... signed arithmetic gives you an effective 2GB process size. Compare and contrast lseek() and lseek64()... sizeof(off_t something). But if you have six 2GB processes running on a 6.x GB system is that useful? Are you playing with one Big process. Do you have a test case or pointer to a test case (best) so folks with large memory systems can sanity test this for you? -- T o m M i t c h e l l Looking for a place to hang my hat. -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
