Messages in this thread | | | Date | Mon, 22 Jun 2009 19:06:25 +0200 | From | Brice Goglin <> | Subject | Re: [RFC PATCH 0/4]: affinity-on-next-touch |
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Lee Schermerhorn wrote: > The primary difference should be at unmap time, right? In the fault > path, I only update the pte of the faulting task. That's why I require > the [anon] pages to be in the swap cache [or something similar]. I > don't want to be fixing up other tasks' page tables in the context of > the faulting task's fault handler. If, later, another task touches the > page, it will take a minor fault and find the [possibly migrated] page > in the cache. Hmmm, I guess all tasks WILL incur the minor fault if > they touch the page after the unmap. That could be part of the > difference if you compare on the same kernel version. >
Agreed.
> Try booting with cgroup_disable=memory on the command line, if you have > the memory resource controller configured in. See what that does to > your measurements. >
It doesn't seem to help. I'll try to bisect and find where the performance dropped.
> ??? I would expect low level page copying to be highly optimized per > arch, and also fairly stable.
I just did a quick copy_page benchmark and didn't see any performance difference between 2.6.27 and mmotm.
thanks, Brice
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