shared libraries (was tracing system calls)

[James Van Artsdalen]

In article <67440 at sun.uucp>, guy at gorodish.Sun.COM (Guy Harris) wrote:

> S5R3 does it in the kernel.  SunOS 4.0 does it in user mode.  [...]

> It also means it's easier to make it more powerful; the SunOS shared
> libraries are not tied to specific locations, and relocation is done
> when the library is mapped in.

What are the performance trade-offs here?  All of Sun's hardware may
support position independent code, but I wonder what the expense would
be of actually relocating the library code on each and every exec() on
a processor where all branches are absolutely addressed.

How do the two schemes fair under existing hardware?  Does it make a
significant difference in the real world?
-- 
James R. Van Artsdalen    ...!uunet!utastro!bigtex!james     "Live Free or Die"
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