dynamic library cost (was RE: libtool, java woes)

Jakub Jelinek jakub@redhat.com
Tue Apr 10 15:00:00 GMT 2001


On Tue, Apr 10, 2001 at 09:15:40AM -0700, Boehm, Hans wrote:
> > From: Alexandre Oliva [ mailto:aoliva@redhat.com ]
> >
> > We either need libsupc++ to be a shared library, that both libstdc++
> > and libgcj depend on, or have libgcj depend on libstdc++.
> > 
> One thing to keep in mind with all of this:
> 
> I'm seeing significant overheads as a result of dynamic library calls.  On a
> PII/300 machine, a (single-threaded) loop containing only free(malloc(8))
> runs more than 20% faster when it's linked statically.  This is similar on
> an Itanium machine.  I'm not sure how significant that is for typical C
> programs, nor how frequently something like libsupc++ is called.  I believe
> it is currently very significant for libgcj and calls to the garbage
> collector library from libgcj.

Not to mention the dynamic linking overhead at startup (or dlopen) time
which every additional shared library adds.

	Jakub



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