The UBC + interactive performance thing came up again in some internal
discussion recently, but this is a better place for it.

First of all, there still seem to be some complains about bad
interactive performance (i.e. program ("text") pages being
paged out because they're being claimed for data).

I noticed that the default value for 'vtextmin', the minimum threshold
for the percentage of pages dedicated to text, is currently 5%. Which
is a bit low, even at 512M this would only get you 25M, which is
easily exceeded by just running X and netscape or mozilla. People
who are seeing problems might want to try setting this at a higher
value of, say, 20%.

Maybe another simple thing to try is 'don't touch text pages, unless
the data pages fall below a certain threshold'. This would
be easy to do (it's all in lines 451-478 in uvm_pdaemon.c).

Lastly, I believe that another problem was that shared libraries
are treated the same as 'normal' data files. Not sure what to
do there, maybe a heuristic that prefers keeps r-x mapped pages?

- Frank

-- 
Frank van der Linden                           fvdl@wasabisystems.com
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