From: jwinstea@fenris.claremont.edu (Jim Winstead Jr.) Subject: Re: shared libs Date: 14 Aug 1992 05:15:38 GMT
In article <1992Aug14.040459.29047@cs.ucf.edu> hab@engr.ucf.edu (Hubert Bahr) writes:
>In article <1992Aug13.183740.24742@ods.com> david@ods.com (David Engel) writes:
>>
>>Yes, there is a slight performance hit but it's not even noticable
>>for most programs. One of these days, when I get the time and
>>inclination, I'm going to do some more accurate benchmarking. The
>>2-4 % I measured a long time ago still seems a little high to me.
>>Of course, nobody is forcing you to use the jump table libs. If you
>>need that last bit of performance, you can always use the regular
>>shared libs.
>
>Not when HJ only provides GCC only as a binary using jump tables for
>it. We are forced to use at least GCC with jump tables.
Ahem. prep.ai.mit.edu:/pub/gnu/gcc-2.2.2.tar.Z, and
banjo.concert.net:/pub/Linux/GCC/gcc-2.2.2.tar.Z will give you the
most current source for GCC. If you're that ocncenred with not using
jump-table libs, compile it yourself. :)
>I for one want to know that I have an up to date source library for all
>the software I use. I also want this library compilable with the current
>make files and utilities. Yes it will take extensive work to automate
>this recompile effort, but I think the dividends are multifold, 1st If
Um, I'm glad you have the diskspace to keep the source around, and the
time to recompile everything. Most of us don't.
>I check things when they have just been changed, the changers will probably
>be more responsive to bug reports. 2 New versions of GCC and libraries
>are usually to fix bugs or performance flaws. How can I take advantage
>of those changes without recompiling anyway. 3. I can take advantage
Most GCC/libc releases are to fix bugs in libc - with jump table
libraries, just copy the new library into place and *all* binaries
linked against the jump table libraries use the new routines. No
recompilation necessary.
>of all information available from GDB to make the programs better. 4 I
Well, you have to link with -g to do anything really special with GDB,
anyways, so you're already linking against static libs in that case.
>In this environment I see absolutely no benefit with jump tables. True
>freedom with software is to have complete control to make desired changes
>without undue suprises.
I would say that you are in an extremely special-case environment. I
doubt anyone else is looking forward to recompiling entire source
trees when each new bugfix to the libraries come out.
There may be a very slight performance hit for using jump table
libraries. I'm willing to take that hit for the amount of time it
will save me - I'm sick of recompiling all the programs I have around
every time a new gcc comes out. With 2.2.2d, it should be the last
time I'll have to recompile for a nice long time.
--
+ Jim Winstead Jr. (CSci '95)
| Harvey Mudd College, WIBSTR
| jwinstea@jarthur.Claremont.EDU
+ or jwinstea@fenris.Claremont.EDU