I. Peter Wong - rmap performance testing
rmap consumes a lot of memory and many pte's. using read (as compared to
readv)  without rmap on 2.5.25 was the only way he was able
to finish the runs. martin said he is running into memory issues
and they know the problem and will have the fixes soon. 
Martin told him to try using threads instead of processes or less 
tasks in general that might help peters runs. there are optimizations
in 2.5.37 that will make rmap take up almost half the space.

Badari asked if he was not able to get any throughput runs yet 
(even without rmap)? Peter said that is true.

II. Duc Vianney - Hyperthreading performance

He is using multithreaded benchmarks. Did not see a big difference between
hyperthreading and no hyperthreading. except in aim 9 sync disk test
there was a 38% degredation. unfortunately the hardware was taken
away so he can not rerun that test right now. eventually he will
get it back and should be able to test it again. Martin asked them
to try to rerun the aim 9 test again since that is the only one
showing interesting results and it should be fixed.

III. Dave McCracken - rmap performance testing (rollup patch backported to
2.5.26)

He wanted to enable testing of base rmap against nonrmap for performance 
testing.  2.5.26 was the release before rmap went in. took the original 
patch that got merged plus some of the basic optimizations against 2.5.26.
performance team tested it and in general showed it was not
a significant cost. some of the tests they ran didnt stress the
areas where it (fork, exec) might have a cost. but akpm is testing
fork and exec. However, when they started testing with volanomark
(paging) it showed some performance hits.

Martin said it wasnt what they were expecting since they thought the
static overhead would be the most cost and would help most wiht
paging. but that wasnt the case at least with this 2.5.26 (also
with -mm1 was slower). so something is still broken there. 
Dave reminded everyone there are other changes in 2.5 besides rmap.
Dave thinks we will just have to live with the instabilities and keep
testing as changes come out and try to abstract out which parts are
memory related and which ones are not.

Badari reminded everyone that 2.5.32 and on is bouncing need akpms scsi_hack 
otherwise you bounce.  It is a one line fix you will need otherwise
you will bounce. but since it is a hack akpm is not pushing it to
Linus.

IV. Martin Bligh - rmap status

Covered most already but we know there are performance issues. linus has
merged the intel large page support patch. going to try to replace
the interface to make it more standard and easier to use. all of
it should be done before halloween. bill hartner asked where intel
has the interface documented. laughter, regarding his optimism.
it would be nice to see it documented though.

bill hartner has a question about large memory reducing tlb misses.
martin increase tlb coverage by a factor of a 1000. how measureable
is the reduction in tlb misses? martin - mostly shown by faster
processes and memory interfaces. mainly win in not stalling the cpu.
bill was thinking about some performance counters to measure stalls.
andi kleen was having horrendous tlb misses using gcc and something?

V. Bill Hartner 

Rik asked for 2.4.19 measurements. baseline with O1 scheduler.
noticed that even on 4bg system should not swap with 2.4 rmap patch. 
even with 1/2 gig free memory it is swapping. martin said to
definitely mail that out. Bill going to rerun with 2bg swap. might
not have those out until monday.