Messages in this thread | | | Date | Wed, 08 Sep 2004 14:54:10 -0500 | From | Ray Bryant <> | Subject | Re: swapping and the value of /proc/sys/vm/swappiness |
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Martin J. Bligh wrote: >>It seems to me that the 5% number in there is more or less arbitrary. >>If we are on a big memory Altix (4 TB), 5% of memory would be 200 GB. >>That is a lot of page cache. > > > For HPC, maybe. For a fileserver, it might be far too little. That's the > trouble ... it's all dependant on the workload. Personally, I'd prefer > to get rid of manual tweakables (which are a pain in the ass in the field > anyway), and try to have the kernel react to what the customer is doing. > I guess we can leave them there for overrides, but a self-tunable default > would be most desirable. >
I agree that tunables are a pain in the butt, but a quick fix would to be at least to add that 5% to the set of stuff settable in /proc/sys/vm. Most workloads/systems won't need to change it. Very large Altix systems could change it if needed.
I don't think that is at the root of the swappiness problems with 2.6.9-rc1-mm3, though.
> For instance, would be nice if we started doing writeback to the spindles > that weren't busy much earlier than if the disks were thrashing. > > M. > >
-- Best Regards, Ray ----------------------------------------------- Ray Bryant 512-453-9679 (work) 512-507-7807 (cell) raybry@sgi.com raybry@austin.rr.com The box said: "Requires Windows 98 or better", so I installed Linux. -----------------------------------------------
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