On Sat 2007-12-22 12:09:59, Arjan van de Ven wrote: > On Tue, 18 Dec 2007 17:06:24 +0000 > Matthew Bloch <[EMAIL PROTECTED]> wrote: > > > Hi - I'm trying to come up with a way of thoroughly testing every byte > > of RAM from within Linux on amd64 (so that it can be automated better > > than using memtest86+), and came up with an idea which I'm not sure is > > supported or practical. > > > > The obvious problem with testing memory from user space is that you > > can't mlock all of it, so the best you can do is about three quarters, > > and hope that the rest of the memory is okay. > > well... to be honest the more obvious problem will be that you won't be > testing the RAM, you'll be testing the CPU's cache.. over and over again. > > memtest86+ does various magic to basically bypass the caches (by disabling > them ;-)... > Doing that in a live kernel situation, and from userspace to boot...... > that's... and issue.
Are you sure? I always assumed that memtest just used patterns bigger than L1/L2 caches... ... and IIRC my celeron testing confirmed it, if I disabled L2 cache in BIOS, memtest behave differently. Anyway, if you can do iopl(), we may as well let you disable caches, but you are right, that will need a kernel patch. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/