Stability and Memory Pressure in 8.2

[Gary C Martin]

On 10 Sep 2008, at 08:27, Marco Pesenti Gritti wrote:

> On Wed, Sep 10, 2008 at 4:29 AM, Gary C Martin  
> <gary at garycmartin.com> wrote:
>> Well, I was hoping to see the numbers go the other way with the
>> rainbow fork trick sharing more module code between Activities. Could
>> be worse I guess – I should also test opening N instances of the same
>> Activity and see which way memory usage has moved in that scenario.
>
> Now that's worrying. Could you try to disable security (remove
> /etc/olpc-security)? That will kill the rainbow trick and comparing
> data should tell us if it's helping  memory at all.


Sure, retested build 759 with and without /etc/olpc-security, same  
test procedure as before:

With /etc/olpc-security removed, a reboot, and all five Activities  
launched, free buffers/cache reports 21Mb more is being used (up to  
192Mb from 171Mb). Though looking at each Activity's footprint shows a  
less clear signal where Write-57 and Record-57 actually have a  
considerably smaller footprint; and Calculate-23, Paint-22, and Moon-4  
have a slightly larger footprint (and shared memory is actually  
reported as having increased).

Write-57
with -> 15.5% (RES=35m, SHR=13m, DATA=20m)
without -> 13.8% (RES=31m, SHR=12m, DATA=18m)

Record-57
with -> 14.2% (RES=32m, SHR=14m, DATA=64m)
without -> 11.5% (RES=26m, SHR=11m, DATA=61m)

Calculate-23
with -> 10.6% (RES=24m, SHR=8m, DATA=15m)
without -> 11.3% (RES=25m, SHR=11m, DATA=13m)

Paint-22
with -> 10.1% (RES=23m, SHR=8m, DATA=14m)
without -> 10.6% (RES=24m, SHR=11m, DATA=12m)

Moon-4
with -> 9.7% (RES=22m, SHR=8m, DATA=13m)
without -> 10.3% (RES=23m, SHR=11m, DATA=11m)

Also I noticed, for some reason, X uses 6-8Mb less resident memory  
with /etc/olpc-security removed. That was unexpected enough for me to  
re-check the results several times:

/usr/bin/X
with -> 7.5% (RES=17m, SHR=13m, DATA=9m)
with -> 7.5% (RES=17m  SHR=13m DATA=9m)

without -> 5.1% (RES=11m, SHR=8m, DATA=9m)
without -> 4.3% (RES=9m, SHR=7m, DATA=9m)

Hmm, so what actually took up the extra 21Mb in total that the rainbow  
trick does appear to be saving us (considering most of the above items  
all add up as memory savings when disabling the rainbow trick)?

I seem to be generating more questions than answers here!

--Gary