Re: [discuss] whats the /lib/libc.so.1 mount for ?

["Joshua M. Clulow via illumos-discuss" <discuss@lists.illumos.org>]

On Fri, 31 Jan 2025 at 09:09, Jason King <jason.brian.king@gmail.com> wrote:
> Newer libraries would likely use linker capabilities to do this in a single library (if the author is aware of them – it’s actually a neat feature that isn’t as well known as it should be IMO). I don’t have access to the relevant history (this all predates illumos), but my best guess is that the linker functionality to allow selection of an optimized implementation of a function based on CPU capabilities probably came later  (and no one’s been interested in doing the work to consolidate them – I suspect it’d get rather tedious).

I think it also depends on how much of the program text ends up having
to change.  In the libc case, though I have not looked at this moment,
it's conceivable that there are a lot of syscall stubs laced
throughout the program text.  A whole-library switch may facilitate
better sharing of pages, or might just be faster to link, etc.  It
would require some investigation and measurement to know one way or
another.


Cheers.

-- 
Joshua M. Clulow
http://blog.sysmgr.org

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