Messages in this thread | | | Date | Sun, 20 Apr 2008 19:19:26 +0200 | From | Andi Kleen <> | Subject | Re: x86: 4kstacks default |
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Jörn Engel wrote: > On Sun, 20 April 2008 16:19:29 +0200, Andi Kleen wrote: >> Only if you believe that 4K stack pages are a worthy goal. >> As far as I can figure out they are not. They might have been >> a worthy goal on crappy 2.4 VMs, but these times are long gone. >> >> The "saving memory on embedded" argument also does not >> quite convince me, it is unclear if that is really >> a significant amount of memory on these systems and if that >> couldn't be addressed better (e.g. in running generally >> less kernel threads). I don't have numbers on this, >> but then the people who made this argument didn't have any >> either :) > > It is not uncommon for embedded systems to be designed around 16MiB.
But these are SoC systems. Do they really run x86? (note we're talking about an x86 default option here)
Also I suspect in a true 16MB system you have to strip down everything kernel side so much that you're pretty much outside the "validated by testers" realm that Adrian cares about.
> When dealing in those dimensions, savings of 100k are substantial. In > some causes they may be the difference between 16MiB or 32MiB, which > translates to manufacturing costs. In others it simply means that the > system can cache
If you need the stack you don't have any less cache foot print. If you don't need it you don't have any either.
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