Messages in this thread | | | Date | Tue, 6 Nov 2007 20:40:09 +0100 | From | Willy Tarreau <> | Subject | Re: x86_64 ten times slower than i386 |
| |
On Mon, Nov 05, 2007 at 05:19:44PM -0800, H. Peter Anvin wrote: > Andi Kleen wrote: > >>Jesse Barnes (cc:d) wrote a patch to address this, I think (x86: trim > >>memory not covered by WB MTRRs), but as far as I can tell it hasn't > >>been merged yet. System is Intel, 4gb of RAM. > > > >It wasn't merged because it broke booting on some systems. > >Besides the memory would be still lost -- all it did was to automate > >the "mem=XXXX" line. > > There really are only two ways to deal with this -- drop the memory > (which should be automated, and a warning printed) or adjust the MTRRs. > The problem is that at some point we run out of MTRRs, partially > because they're masks instead of base/limit.
Just out of curiosity, what would be the problem if the MTRRs covered more than the memory size ? For instance, instead of having 512 MB at 4G, why not have 1G at 4G ?
regards, Willy
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |