On Sun, Aug 18, 2019 at 2:33 PM Hans de Goede <hdego...@redhat.com> wrote:

>
> >      > Adding -ffunction-sections -fdata-sections to defaults can help
> considerably in producing smaller binaries, and is not the default.
> >      > Linking with -Wl,--gc-sections helps a lot and is not the default
> >
> >     These OTOH are interesting I know that e.g. uboot combines these and
> it helps a lot to get smaller binaries,
> >     and this should help with RAM size too, since if a page of a binary
> contains mostly unused things and 1 symbol
> >     which is actually used it will still get paged in.
> >
> >     Can you perhaps start a new devel list thread about just this ?
> Maybe with some binary size numbers for
> >     some apps / libs build with and without these options?
> >
> >
> > It's pretty well documented in various articles, e.g.:
> > https://wiki.wxwidgets.org/Reducing_Executable_Size
> > It also covers how much difference -Os can make.
>
> Interesting, thank you for that link.
>
>
> >      > Extensive stripping seems to already be the default
> (--strip-unneeded, removal of .comment and .note sections)
> >      >
> >      > 2) Runtime condiguration
> >      > Default stack size is 8192 (ulimit -s). This unnecessarily eats a
> considerably amount of memory. I have yet to see anything that actually
> experiences problems with 1M.
> >
> >     Actually ulimit -s is the *maximum* stack size, I'm pretty sure the
> stack will start much smaller and
> >     grow dynamically. So changing this is not saving any RAM and it will
> makes apps which do have high
> >     stack usage crash when they hit the new lower limit.
> >
> >
> > Either way, it makes a noticeable difference to memory consumption on a
> very memory constrained system without any other obvious adverse effects.
>
> Interesting unless I'm reading the manpage wrong, "ulimit -s" sets the
> maximum stack-size.
> Maybe that also influences the initial sizing of the stack ?
>

I believe it does. Or at least that is the only explanation I can come up
with for the observation.


>
> Can someone who knows more about this shed some light on this? Is there a
> way to go with
> a smaller initial stack-size without changing the maximum size?
>

It may be simpler to approach the question from the other side, i.e. is
there anything that actually ever needs more than 1MB of stack space? If
there is, I haven't seen it in the decade since I've been using this tweak
with various Fedora derived distributions.
_______________________________________________
devel mailing list -- devel@lists.fedoraproject.org
To unsubscribe send an email to devel-le...@lists.fedoraproject.org
Fedora Code of Conduct: 
https://docs.fedoraproject.org/en-US/project/code-of-conduct/
List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
List Archives: 
https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org

Reply via email to