Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 30 Dec 2003 17:34:11 -0800 | From | Andrew Morton <> | Subject | Re: 2.6.0 performance problems |
| |
Thomas Molina <tmolina@cablespeed.com> wrote: > > On Tue, 30 Dec 2003, Linus Torvalds wrote: > > Ok. This looks much closer to the 2.4.x numbers you reported: > > > > real 13m50.198s > > user 0m33.780s > > sys 0m15.390s > > > > so I assume that we can consider this problem largely solved? There's > > still some difference, that could be due to just VM tuning.. > > > > I suspect that what happened is: > > - slab debugging adds a heavy CPU _and_ it also makes all the slab caches > > much less dense. > > - as a result, you see much higher system times, and you also end up > > needing much more memory for things like the dentry cache, so your > > memory-starved machine ended up swapping a lot more too. > > So you are telling me that I am paying the price for running development > kernels and enabling all the debugging.
CONFIG_DEBUG_PAGEALLOC really does hurt on small machines. Mainly because it rounds the size of all slab object which are >= 128 bytes up to a full 4k. So things like inodes and dentries take vastly more memory.
The other debug options are less costly.
- 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/
| ![\](/images/icornerr.gif) |