Messages in this thread | | | Subject | Re: Overhead of highpte | From | Dave Hansen <> | Date | 03 Jul 2003 19:34:19 -0700 |
| |
On Wed, 2003-07-02 at 15:53, Martin J. Bligh wrote: > Some people were saying they couldn't see an overhead with highpte. > Seems pretty obvious to me still. It should help *more* on the NUMA > box, as PTEs become node-local. > > The kmap_atomic is, of course, perfectly understandable. The increase > in the rmap functions is a bit of a mystery to me. > > M. > > Kernbench: (make -j vmlinux, maximal tasks) > Elapsed System User CPU > 2.5.73-mm3 45.38 114.91 565.81 1497.75 > 2.5.73-mm3-highpte 46.54 130.41 566.84 1498.00
OK, let's add to the mystery. Here's my run, on virtually the same hardware except, I don't do a bzImage. bzImage is pretty useless because I don't want to benchmark gzip, so I just do vmlinux. My times should be _faster_ than yours, right?
Elapsed: User: System: CPU: 2.5.73-mjb2 77.008s 937.756s 90s 1334% 2.5.73-mjb2-highpte 76.756s 935.464s 93.116s 1339%
Yeah, system time goes up. Something funky is going on. We should have the same machines, except that I have twice the RAM, right? What kind of fs are you doing your tests on? I'm doing ramfs.
-- Dave Hansen haveblue@us.ibm.com
- 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/
| |