Messages in this thread | | | Date | Thu, 24 Feb 2005 13:41:21 +1100 | From | Nick Piggin <> | Subject | Re: More latency regressions with 2.6.11-rc4-RT-V0.7.39-02 |
| |
Lee Revell wrote: > On Thu, 2005-02-24 at 12:29 +1100, Nick Piggin wrote: > >>Lee Revell wrote: >> >>>IIRC last time I really tested this a few months ago, the worst case >>>latency on that machine was about 150us. Currently its 422us from the >>>same clear_page_range code path. >>> >> >>Well it should be pretty trivial to add a break in there. >>I don't think it can get into 2.6.11 at this point though, >>so we'll revisit this for 2.6.12 if the clear_page_range >>optimisations don't get anywhere. >> > > > Agreed, it would be much better to optimize this away than just add a > scheduling point. It seems like we could do this lazily. >
Oh? What do you mean by lazy? IMO it is sort of implemented lazily now. That is, we are too lazy to refcount page table pages in fastpaths, so that pushes a lot of work to unmap time. Not necessarily a bad trade-off, mind you. Just something I'm looking into.
- 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/
| |