On 12/05/11 05:24, Gabe Black wrote: > On 12/03/11 13:02, Nilay Vaish wrote: >> On Wed, 30 Nov 2011, Gabriel Michael Black wrote: >> >>> That may be the same thing that's happening with Ali's branch >>> predictor patch. With Ruby execution changes enough to hit one of the >>> broken squashing cases. The Ruby integration is probably working. >>> >>> Gabe >>> >>> Quoting Nilay Vaish <[email protected]>: >>> >>>> Gabe, when I boot FS with O3 CPU and Ruby, I get the following >>>> output on the terminal of the simulated system. >>>> >>>> EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended >>>> VFS: Mounted root (ext2 filesystem). >>>> Freeing unused kernel memory: 232k freed >>>> init[1]: segfault at ffffffff802095c0 rip ffffffff802095c8 rsp >>>> 00007fff38fa81b8 error 15 >>>> init[1]: segfault at ffffffff802095c0 rip ffffffff802095c8 rsp >>>> 00007fff38fa81b8 error 15 >>>> >>>> The segfault message keeps appearing. Do you know why this might be >>>> happening? >>>> >> Gabe, how can I confirm this? Is there something that I can do to >> resolve the problem with branch prediction? >> >> Thanks >> Nilay >> _______________________________________________ >> gem5-dev mailing list >> [email protected] >> http://m5sim.org/mailman/listinfo/gem5-dev > I'm fairly confident that's what's going on. The stack address is user > space and the instruction pointer is in kernel space. The page fault is > from near the ip, and the error code is 15 which means, if I'm not > mistaken, a permission problem on fetch. You can't easily fix the > problem, but if you want to get started the first step would be to clean > up the squashing mechanisms in O3 like I brought up in that email a > while ago. The real problem is that squashing doesn't always preserve > enough state (the macroop instance specifically) in all situations, and > that the squashing stuff is too ad-hoc and all over the place to really > fix it correctly and know that it's correct. I'd thought I fixed it > before when I fixed one particular squash path, but obviously I didn't > get it all. > > Gabe > _______________________________________________ > gem5-dev mailing list > [email protected] > http://m5sim.org/mailman/listinfo/gem5-dev
What was unclear about this email and the ones before it? Did you not believe me for some reason? You've spent about a month partially rediscovering what I explained in them. I've already said how this needs to be fixed. Gabe _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
