massive increase of the size of the library

massive increase of the size of the library

[Paul Zimmermann]

       Hi,

some user reported us that the size of the MPFR library did increase a lot
between 4.0.2 and 4.1.0. I notice a similar fact for the GNU libc, between
2.28 and 2.29, both for libc.a and libc.so (the same holds for libm.a and
libm.so):

-rw-r--r-- 1 zimmerma caramba  5121680 May 20 10:49 /localdisk/zimmerma/glibc-2.28/build/libc.a
-rw-r--r-- 1 zimmerma caramba 45919382 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.a

-rwxr-xr-x 1 zimmerma caramba  2092096 May 20 11:07 /localdisk/zimmerma/glibc-2.28/build/libc.so
-rwxr-xr-x 1 zimmerma caramba 18769880 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.so

We see an increase in size by a factor of almost 10!

2.28 was configured with --without-selinux, but if I configure 2.29 with
--without-selinux, I get similar figures as the 2.29 ones above. Also 2.28 was
compiled with gcc 9.3.0, whereas 2.29 was compiled with gcc 9.2.1, but
compiling 2.29 with gcc 9.3.0 does not change much too.

Does anybody know the reason of that massive increase?

Paul

Re: massive increase of the size of the library

[Florian Weimer]

* Paul Zimmermann:

> some user reported us that the size of the MPFR library did increase a lot
> between 4.0.2 and 4.1.0. I notice a similar fact for the GNU libc, between
> 2.28 and 2.29, both for libc.a and libc.so (the same holds for libm.a and
> libm.so):
>
> -rw-r--r-- 1 zimmerma caramba  5121680 May 20 10:49 /localdisk/zimmerma/glibc-2.28/build/libc.a
> -rw-r--r-- 1 zimmerma caramba 45919382 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.a
>
> -rwxr-xr-x 1 zimmerma caramba  2092096 May 20 11:07 /localdisk/zimmerma/glibc-2.28/build/libc.so
> -rwxr-xr-x 1 zimmerma caramba 18769880 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.so
>
> We see an increase in size by a factor of almost 10!

Can you put the file somewhere?  My first guess would be that it's
debugging information.  The “size” tool from binutils shows numbers
without debugging information.

Thanks,
Florian

Re: massive increase of the size of the library

[Paul Zimmermann]

       Dear Florian,

> From: Florian Weimer <fweimer@redhat.com>
> Cc: libc-alpha@sourceware.org,  Vincent.Lefevre@ens-lyon.fr
> Date: Tue, 21 Jul 2020 10:26:04 +0200
> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux)
> 
> * Paul Zimmermann:
> 
> > some user reported us that the size of the MPFR library did increase a lot
> > between 4.0.2 and 4.1.0. I notice a similar fact for the GNU libc, between
> > 2.28 and 2.29, both for libc.a and libc.so (the same holds for libm.a and
> > libm.so):
> >
> > -rw-r--r-- 1 zimmerma caramba  5121680 May 20 10:49 /localdisk/zimmerma/glibc-2.28/build/libc.a
> > -rw-r--r-- 1 zimmerma caramba 45919382 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.a
> >
> > -rwxr-xr-x 1 zimmerma caramba  2092096 May 20 11:07 /localdisk/zimmerma/glibc-2.28/build/libc.so
> > -rwxr-xr-x 1 zimmerma caramba 18769880 Mar  6 07:58 /localdisk/zimmerma/glibc-2.29/build/libc.so
> >
> > We see an increase in size by a factor of almost 10!
> 
> Can you put the file somewhere?  My first guess would be that it's
> debugging information.  The “size” tool from binutils shows numbers
> without debugging information.
> 
> Thanks,
> Florian

sure, the files are here:

https://members.loria.fr/PZimmermann/libc-2.28.a
https://members.loria.fr/PZimmermann/libc-2.28.so
https://members.loria.fr/PZimmermann/libc-2.29.a
https://members.loria.fr/PZimmermann/libc-2.29.so

Paul

Re: massive increase of the size of the library

[Florian Weimer]

* Paul Zimmermann:

> sure, the files are here:
>
> https://members.loria.fr/PZimmermann/libc-2.28.a
> https://members.loria.fr/PZimmermann/libc-2.28.so
> https://members.loria.fr/PZimmermann/libc-2.29.a
> https://members.loria.fr/PZimmermann/libc-2.29.so

   text	   data	    bss	    dec	    hex	filename
1753624	  20968	  16408	1791000	 1b5418	libc-2.28.so
1758304	  20968	  16408	1795680	 1b6660	libc-2.29.so

So the actual code is of the same size.

The difference seems to be that the second file contains debugging
information:

$ strip libc-2.2?.so
$ ls -l libc-2.2?.so
-rw-rw-r--. 1 fweimer fweimer 1791400 Jul 21 10:39 libc-2.28.so
-rw-rw-r--. 1 fweimer fweimer 1791400 Jul 21 10:39 libc-2.29.so

So it must be a difference in your build environment.

Thanks,
Florian

Re: massive increase of the size of the library

[Paul Zimmermann]

> From: Florian Weimer <fweimer@redhat.com>
> Date: Tue, 21 Jul 2020 10:40:13 +0200
> 
> * Paul Zimmermann:
> 
> > sure, the files are here:
> >
> > https://members.loria.fr/PZimmermann/libc-2.28.a
> > https://members.loria.fr/PZimmermann/libc-2.28.so
> > https://members.loria.fr/PZimmermann/libc-2.29.a
> > https://members.loria.fr/PZimmermann/libc-2.29.so
> 
>    text	   data	    bss	    dec	    hex	filename
> 1753624	  20968	  16408	1791000	 1b5418	libc-2.28.so
> 1758304	  20968	  16408	1795680	 1b6660	libc-2.29.so
> 
> So the actual code is of the same size.
> 
> The difference seems to be that the second file contains debugging
> information:
> 
> $ strip libc-2.2?.so
> $ ls -l libc-2.2?.so
> -rw-rw-r--. 1 fweimer fweimer 1791400 Jul 21 10:39 libc-2.28.so
> -rw-rw-r--. 1 fweimer fweimer 1791400 Jul 21 10:39 libc-2.29.so
> 
> So it must be a difference in your build environment.
> 
> Thanks,
> Florian

thanks Florian. Indeed I had to compile 2.28 with CFLAGS="-O2 -Wno-error"
since with -Werror it does not compile with gcc 9.3.0. If I add -g then
I get a similar size than with 2.29 (where CFLAGS="-O2 -g" by default).

Paul

Re: massive increase of the size of the library

[Joseph Myers]

On Tue, 21 Jul 2020, Paul Zimmermann wrote:

> thanks Florian. Indeed I had to compile 2.28 with CFLAGS="-O2 -Wno-error"
> since with -Werror it does not compile with gcc 9.3.0. If I add -g then

The way to disable -Werror is the --disable-werror configure option.  
(There's also the option of identifying the commits that fixed the build 
with newer GCC and cherry-picking them to the older release branch.)

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: massive increase of the size of the library

[Andreas Schwab]

On Jul 21 2020, Paul Zimmermann wrote:

> https://members.loria.fr/PZimmermann/libc-2.28.a
> https://members.loria.fr/PZimmermann/libc-2.28.so
> https://members.loria.fr/PZimmermann/libc-2.29.a
> https://members.loria.fr/PZimmermann/libc-2.29.so

You are comparing apples (stripped) with oranges (unstripped).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."